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#HNBO 3.0 Program Manual#N




#N(#INatural Bond Orbital / Natural  Population  Analysis  /
Natural Localized Molecular Orbital Programs#N)





E. D. Glendening, A. E. Reed,9agger  J.  E.  Carpenter,9dagger
and F. Weinhold

#ITheoretical Chemistry Institute and Department of  Chemis-
try, University of Wisconsin, Madison, Wisconsin 53706#N





92717.#N









0 The various natural localized sets can be  considered
to result from a sequence of transformations of the in-
put atomic orbital basis set {
_______________

9agger #C#RNote, however, that some electronic structure
packages do not make provision for calculating the spin
density matrices for some types of open-shell wavefunc-
tions (e.g., MCSCF wavefunctions calculated by the GUGA
formalism in the GAMESS system), so that  NBO  analysis
cannot be applied in these cases.#O

9dagger #C#RIf the wavefunction is not calculated in  an
atom-centered basis set, it would be necessary to first
compute a wavefunction for each isolated  atom  of  the
molecule  (in  the actual basis set and geometry of the
molecular calculation), then select the most highly oc-
cupied  natural orbitals of each atomic wavefunction to
compose a  final  set  of  linearly  independent  atom-
centered  basis functions of the required dimensionali-
ty.  Since atom-centered basis functions are the nearly
universal   choice   for  molecular  calculations,  the
current
_________________________

                       July 11, 1995





                           - 2 -


NBO program makes no provision for this step.#O

Guide, Section C.
+0 +lf 0>>
+0 +lf 0//'
|<<3//15//75//8//35>>|7____________________99____________________
-dwid +0 ipen //+0 +dht ipen //+dhlfwid +0 ipen >>
  input basis7 arr  NAOs7 arr  NHOs7 arr  NBOs7 arr  NLMOs
  _________________________

  Each natural localized set forms a complete orthonormal
  set  of  one-electron functions for expanding the delo-
  calized molecular  orbitals  (MOs)  or  forming  matrix
  representations of one-electron operators.  The overlap
  of associated ``pre-orthogonal'' NAOs (PNAOs),  lacking
  only  the interatomic orthogonalization step of the NAO
  procedure, can be used to estimate the strength of  or-
  bital interactions in the usual way.

  0 The optimal condensation of occupancy in the  natural
  localized orbitals leads to partitioning into high- and
  low-occupancy orbital types (reduction in dimensionali-
  ty  of  the  orbitals having significant occupancy), as
  reflected in the orbital labelling.  The small  set  of
  most  highly-occupied  NAOs,  having a close correspon-
  dence with the effective minimal  basis  set  of  semi-
  empirical  quantum  chemistry,  is  referred  to as the
  ``natural minimal basis'' (NMB) set.  The NMB  (core  +
  valence)  functions  are  distinguished from the weakly
  occupied  ``Rydberg''  (extra-valence-shell)  functions
  that  complete the span of the NAO space, but typically
  make  little  contribution  to  molecular   properties.
  Similarly in the NBO space, the highly occupied NBOs of
  the natural Lewis structure can be  distinguished  from
  the  ``non-Lewis''  antibond  and Rydberg orbitals that
  complete the span of  the  NBO  space.   Each  pair  of
  valence hybrids ,  in the NHO basis give rise to a bond
  (b ) and antibond (ab ) in the NBO basis,

  b  =  ab  =
  the former a Lewis (L) and the latter a non-Lewis  (NL)
  orbital.   The antibonds (valence shell non-Lewis orbi-
  tals) typically play the  primary  role  in  departures
  (delocalization) from the idealized Lewis structure.

  0 The NBO program also makes  extensive  provision  for
  energetic  analysis  of  NBO interactions, based on the
  availability of a 1-electron effective energy  operator
  (Fock  matrix) for the system.  Estimates of energy ef-
  fects are based on second-order perturbation theory, or
  on  the  effect  of deleting certain orbitals or matrix
  elements and recalculating the total energy.  NBO ener-
  gy  analysis  is dependent on the specific ESS to which
  the NBO program is attached, as described in the Appen-



                       July 11, 1995





                           - 3 -


F x y t 0.0001 0.5 .05 dpx dpy  0 1 ipen //+radius +0 0//  F
x  ym  t  0.0001  0.5 .05 dpx dpy  0 1 ipen // +0 +dht  ipen
//+diam  -dht  0//+0 +dht  ipen //-radius  +0 0// F x  ym  t
0.0001  -0.5  -0.05  dpx  dpy   0  1 ipen // +radius -dhlfht
0//'ext
_________________________
  dix.

  0 The program is provided in a core set of NBO routines
  that  can be attached to an electronic structure system
  of the user's choice.  In addition,  specific  `driver'
  routines are provided that facilitate the attachment to
  popular  #Iab  initio#N  and  semi-empirical   packages
  (GAUSSIAN-8X,  GAMESS, HONDO, AMPAC, etc.).  These ver-
  sions are described in individual Appendices.


  #IA.1.2 #IStructure of the NBO Program#N

  0 The overall logical structure of the NBO program  and
  its  attachment to an electronic structure system (ESS)
  are illustrated in the block  diagram,  Fig.  1.   This
  figure  illustrates  how  the ESS and its scratch files
  (in the upper part of the diagram) communicate  through
  the  interface routines RUNNBO, FEAOIN, and DELSCF with
  the main NBO modules and associated direct access  file
  (in the lower part).

  0 The main NBO program is represented  by  modules  la-
  belled ``NBO'' and ``NBOEAN.''  These refer to the con-
  struction  of  NBOs   (including   natural   population
  analysis, construction of NAOs, NLMOs, etc.) and to NBO
  energy analysis, respectively.  Each module consists of
  subroutines  and  functions  that  perform the required
  operations.  These two  modules  communicate  with  the
  direct-access   disk  file  NBODAF  (LFN  48,  labelled
  ``FILE48'' elsewhere in this manual)  that  is  created
  and  maintained  by  the NBO routines.   Details of the
  NBO and NBOEAN  modules,  common  blocks,  and  direct-
  access  file  are  described in the Programmer's Guide,
  Section C.

  0 The NBO program blocks communicate with the  attached
  ESS through three system-dependent `driver' subroutines
  (RUNNBO, FEAOIN, DELSCF).  The purpose of these drivers
  is  to  load  needed information about the wavefunction
  and various matrices into the FILE48 direct access file
  and  NBO  common  blocks.   Although the ESS is usually
  thought of as `driving' the NBO program, from the point
  of view of the NBO program the ESS is merely a `device'
  that provides initial input (e.g., a density matrix and
  label  information) or other feedback (a calculated en-
  ergy value) upon request.  Each such ESS device  there-
  fore  requires  special  drivers  to make this feedback



                       July 11, 1995





                           - 4 -


' 2//+0 +lf 0//'file' 2>>
#BFigure 1:#N Schematic diagram depicting flow  of  informa-
tion  between  the electronic structure system (ESS) and the
NBO program, and the commun#|ication lines connecting  these
programs
_________________________
  possible.  Versions of the driver subroutines  are  in-
  cluded  for  several popular packages.  The driver rou-
  tines are described in more detail in the  Programmer's
9  agger  #RPresent address: Bayer AG, Abteilung AV-IM-AM,
  5090  Leverkusen,  Bayerwerk,  Federal Republic of Ger-
  many.

9  dagger  #RPresent  address:  Department  of  Chemistry,
  University  of  California-Irvine,  Irvine,  California
  #HTable of Contents#N

















  #HPREFACE: HOW TO USE THIS MANUAL#N



  0 The NBO manual is divided into three major sections:

  0 Section A (``General Introduction and Installation'')
  contains  general  introductory and `one-time' informa-
  tion for the novice user: what the program  does,  pro-
  gram  structure  and  relationship to driver electronic
  structure package, initial installation, `quick  start'
  sample  input data, and a brief tutorial on sample out-
  put.

  0 Section B (``NBO User's Guide'') is  for  the  inter-
  mediate  user  who has an installed program and general
  familiarity with the standard (default) options of  the
  NBO  program.   This  section  documents  the  list  of
  #Ikeywords#N that can be used to alter the standard NBO
  job  options,  with  examples  of the resulting output.
  This section is mandatory for users who wish to use the



                       July 11, 1995





                           - 5 -


to  the  ESS  scratch  file  (called  the  ``dictionary
file,''  ``read-write file,'' etc., in various systems)
and the NBO direct access file (NBODAF).   Heavier  box
borders  mark the ESS-specific driver routines (RUNNBO,
FEAOIN,
_________________________
  program  to  its full potential, to `turn off' or `turn
  on' various NBO options for their specialized  applica-
  tions.

  0 Section C (``NBO Programmer's Guide'') is for  accom-
  plished programmers who are interested in program logic
  and the detailed layout of the source code.  This  sec-
  tion describes the relationship of the source code sub-
  programs to the published algorithms for NAO, NBO,  and
  NLMO determination, providing documentation at the lev-
  el of individual common blocks, functions, and  subrou-
  tines.   This in turn serves as a bridge to the `micro-
  documentation' included as  comment  statements  within
  the  source  code.   Section C also provides guidelines
  for constructing `driver' routines to  attach  the  NBO
  programs to new electronic structure packages.

  #HSection A: GENERAL INTRODUCTION AND INSTALLATION#N


  #BA.1 INTRODUCTION TO THE NBO PROGRAM#N

  #IA.1.1 #IWhat Does the NBO Program Do?#N

  0 The NBO program performs  the  analysis  of  a  many-
  electron  molecular  wavefunction in terms of localized
  electron-pair `bonding' units.  The program carries out
  the  determination  of  natural atomic orbitals (NAOs),
  natural hybrid orbitals (NHOs), natural  bond  orbitals
  (NBOs),   and   natural  localized  molecular  orbitals
  (NLMOs), and uses these to perform  natural  population
  analysis (NPA), NBO energetic analysis, and other tasks
  pertaining to localized analysis of  wavefunction  pro-
  perties.   The  NBO method makes use of only the first-
  order reduced density matrix of the  wavefunction,  and
  hence   is   applicable  to  wavefunctions  of  general
  mathematical form; in the open-shell case, the analysis
  is performed in terms of ``different NBOs for different
  spins,'' based on distinct density  matrices  for  lpha
  and777777  t99a999999   s99p99i99n99.99999999999999999a99g99g777777r   This section provides a brief introduction
  to NBO algorithms and nomenclature.

  0 NBO analysis is  based  on  a  method  for  optimally
  transforming  a given wavefunction into localized form,
  corresponding to the  one-center  (``lone  pair'')  and
  two-center  (``bond'')  elements of the chemist's Lewis
  structure picture.  The  NBOs  are  obtained  as  local
  block  eigenfunctions  of  the one-electron density ma-



                       July 11, 1995





                           - 6 -


DELSCF) that directly interface the ESS  program.   The
heavy  dashed  lines  denote calls from the NBO program
`backward' to the ESS program for information needed to
carry out its tasks.  Otherwise, the sequential flow of
program control is generally from  top  to  bottom  and
from left to right in the diagram.


#IA.1.3 #IInput and Output#N

0 From the user's point of view, the #_input#/  to  the
NBO  program attached to an ESS program consists simply
of one or more keywords (an NBO  #Ikeylist#N)  included
in  the  ESS  input  file.   In effect, the NBO program
reads these keywords to set various job  options,  then
interrogates  the  ESS  program  through the DELSCF and
FEAOIN drivers for  additional  information  concerning
the wavefunction.  The general form of NBO keylists and
the specific functions associated with each keyword are
detailed in the User's Guide, Section B.  The method of
including NBO keylists in the input file for  each  ESS
is detailed in the specific Appendix for the ESS.

0 The following information is passed from the  ESS  to
the NBO program (transparent to the user):

The  one-electron  density  matrix  #BD#N  (or  density
matrices  in  the open-shell case) in the chosen atomic
orbital (AO) basis set;

The AO overlap  matrix  #BS#N,  and  label  information
identifying  the  symmetry  (angular momentum type) and
location (number of the atom to which affixed) for each
AO;

Atomic number (nuclear charge) of each atom.

Certain additional information is written on the FILE48
direct  access  file  and  may  be  used in response to
specific job options, such as the AO Fock matrix #BF#N,
if  energy  analysis is requested; the AO dipole matrix
#BM#N, if  dipole  moment  analysis  is  requested;  or
information concerning the mathematical form of the AOs
(orbital exponents, contraction coefficients, etc.), if
orbital
_________________________
  trix, and are hence ``natural'' in the sense of  L8mlaut
  owdin,   having   optimal  convergence  properties  for
  describing the electron  density.   The  set  of  high-
  occupancy  NBOs, each taken doubly occupied, is said to
  represent  the  ``natural  Lewis  structure''  of   the
  molecule.  Delocalization effects appear as weak depar-
  tures from this idealized localized picture.




                       July 11, 1995





                           - 7 -


plotting information is requested to be saved as  input
for a contour plotting program.

0 The principal #_output#/ from the  NBO  program  con-
sists  of  the  tables  and  summaries  describing  the
results of NBO analysis, included  in  the  ESS  output
file.   Sample NBO output is described in Section A.2.4
below.  If requested, the NBO program  may  also  write
out  transformation  matrices  or  other  data  to disk
files.  The NBO program also  creates  or  updates  two
files,   the   direct-access   file  (FILE48)  and  the
`archive' file (FILE47) that can be used to repeat  NBO
analysis  with  different  options, without running the
ESS program to recalculate the wavefunction.  Necessary
details of these files are given in Section B.7 and the
Programmer's Guide, Section C.


#IA.1.4 #IGeneral Capabilities and Restrictions#N

0 Principal capabilities of the NBO program are:

Natural population, natural bond orbital,  and  natural
localized molecular orbital analysis of SCF, MCSCF, CI,
and M0t oller-Plesset wavefunctions  (main  subroutine:
NBO);

For RHF closed-shell and UHF wavefunctions only,  ener-
getic  analysis  of  the  wavefunction  in terms of the
interactions (Fock matrix elements) between NBOs  (main
subroutine: NBOEAN);

Localized analysis of molecular dipole moment in  terms
of  NLMO  and  NBO  bond moments and their interactions
(main subroutine: DIPANL).

0 A highly transportable subset of standard FORTRAN  77
is employed, with no special compiler extensions of any
vendor, and all variable names  of  six  characters  or
less.  Common abbreviations used in naming subprograms,
variables, and keywords are:

= overlap matrix = density matrix (or D) = Fock  matrix
=  dipole  matrix  (or  DXYZ,  or DX, DY, DZ) = Natural
Population Analysis = Natural Atomic Orbital =  Natural
Bond  Orbital  =  Natural Localized Molecular Orbital =
pre-orthogonal NAO (i.e., omit interatomic orthogonali-
zation) hsp

0 Most of the NBO storage is allocated dynamically,  to
conform  to the minimum required for the molecular sys-
tem under study.  However, certain NBO common blocks of
fixed  dimensionality  are  used  for  integer storage.
These are currently dimensioned to accomodate up to  99



                       July 11, 1995





                           - 8 -


atoms
and 500 basis functions.   Section  C.3  describes  how
these  restrictions can be altered.  The program is not
set up to handle complex wavefunctions, but  can  treat
any  real RHF, ROHF, UHF, MCSCF (including GVB), CI, or
M0t oller-Plesset-type wavefunction (i.e., any form  of
wavefunction  for  which the requisite density matrices
are available) for ground or excited states of  general
open- or closed-shell molecules.  Effective core poten-
tials (``pseudo#|potentials'') can be handled,  includ-
ing  complete  neglect  of core electrons as assumed in
semi-empirical treatments.  The  atomic  orbital  basis
functions  (up  to  #If#N orbitals in angular symmetry)
may be of  general  Slater-type,  contracted  Gaussian-
type,  or  other  general  composition,  including  the
``effective'' ortho#|normal valence-shell AOs of  semi-
empirical  treatments.   AO basis functions are assumed
to be normalized, but in general non-orthogonal.


#IA.1.5  #IReferences  and  Relationship  to   Previous
Versions#N

0 This program (``version 3.0'')  is  an  extension  of
previous versions of the NBO method incorporated in the
semi-empirical program #IBONDO#N [F. Weinhold,  #IQuan-
tum Chemistry Program Exchange No. 408#N (1980); ``ver-
sion 1.0''] and in a GAUSSIAN-82 implementation [A.  E.
Reed  and  F. Weinhold, #IQCPE Bull. #B5#N, 141 (1985);
``version 2.0''], and should be considered to  supplant
those versions.  Version 3.0 also supplants the various
specific versions (``the GAMESS version,'' ``the  AMPAC
version,''  etc.) that have been informally created and
distributed to individual users outside the QCPE frame-
work.

Principal contributors to the development  of  the  NBO
methods and programs (1975-1990) are


Principal references to the  development  and  applica-
tions of NAO/NBO/NLMO methods are:


J. P. Foster and  F.  Weinhold,  #IJ.  Am.  Chem.  Soc.
#B102#N, 7211-7218 (1980).


A. E. Reed and F. Weinhold, #IJ.  Chem.  Phys.  #B78#N,
4066-4073  (1983);  A. E. Reed, R. B. Weinstock, and F.
Weinhold, #IJ. Chem. Phys. #B83#N, 735-746 (1985).


 A. E. Reed and F. Weinhold, #IJ. Chem.  Phys.  #B83#N,



                       July 11, 1995





                           - 9 -


1736-1740
(1985).


J. E. Carpenter and F. Weinhold,  #IJ.  Molec.  Struct.
(Theochem)  #B169#N,  41-62  (1988);  J.  E. Carpenter,
#IPh. D. Thesis#N, University  of  Wisconsin,  Madison,
1987.


A. E. Reed, L. A. Curtiss,  and  F.  Weinhold,  #IChem.
Rev. #B88#N, 899-926 (1988); F. Weinhold and J. E. Car-
penter, in, R. Naaman and Z. Vager (eds.), ``The Struc-
ture  of Small Molecules and Ions,'' (Plenum, New York,
1988), pp. 227-236.

0 The principal enhancements of version 3.0 include:

#IGeneralized  Program  Interface.#N  Overall   program
organization  (Fig. 1) has been modified to standardize
communication with the main ESS program.  This  insures
that  all  special  ESS ``versions'' of the NBO program
now have consistent options and capabilities  (as  long
as the option is meaningful in the context of the ESS),
and enables the program to  be  offered  in  a  greater
number of specialized ESS versions than were previously
available.

#INAO/NPA Summary Table.#N  New  tables  give  improved
display  of NAOs and natural populations, including the
``natural electron configuration'' of each atom  (i.e.,
the  occupancy  and  type of NAOs describing the atomic
electron configuration of each atom).  The new NAO sum-
mary tables (Section A.3.2) include an SCF atomic orbi-
tal energy (if available), a conventional atomic  orbi-
tal  label (1#Is#N, 2#Is#N, 2#Ip#N, etc., in accordance
with the labelling in  isolated  atoms),  and  a  shell
designation  (Cor  = core, Val = valence, or Ryd = Ryd-
berg) to aid characterization of the NAO.

#INBO Summary Table.#N A new NBO summary table (Section
A.3.6)  has  been  provided to summarize the energetics
and delocalization  patterns  of  the  principal  NBOs.
This succinctly combines the most important information
from the full NBO table, diagonal NBO Fock matrix  ele-
ments, and 2nd-order energy analysis.

#IBond Bending Analysis.#N The program includes  a  new
analysis  of hydrid directionality and bond ``bending''
(keyword BEND, Section A.3.4).

#IDipole Moment Analysis.#N The  program  includes  new
optional  provision (keyword DIPOLE, Section B.6.3) for
analysis of the molecular dipole  moment  in  terms  of



                       July 11, 1995





                           - 10 -


localized
NLMOs and NBOs.

#IPrint options.#N The program  offers  new  structured
printing options (Section B.2.4) that give greater con-
venience and flexibility in controlling printed output,
with  improved provision for printing matrices or basis
transformations involving general NAO, NHO,  NBO,  NLMO
or pre-orthogonal (PNAO, PNHO, PNBO, PNLMO) basis sets.

#IOrbital Contour Info.#N The  program  makes  optional
provision (keyword PLOT, Section B.2.5) for writing out
files that can be used by an orbital  plotting  program
(available  separately  through  QCPE)  to draw contour
diagrams of the NBOs or other natural  localized  orbi-
tals.

#IEffective Core Potentials.#N The program now  handles
effective  core potentials (pseudo#|potentials), or the
complete  neglect  of  core  levels  characteristic  of
semi-empirical wavefunctions (Section B.6.12).

The program also  includes  three  changes  to  correct
problems  of  the  previous  version  (which  may  have
affected a small number of users):

#IUnpolarized  Cores.#N  NAOs  identified  as  ``core''
orbitals  are now auto#|matically carried over as unhy-
bridized 1-center core NBOs (Section  B.3).   This  has
virtually  no effect on the form or occupancy of a core
NBO, but averts the (rare) problem of unphysical mixing
between  core  and valence lone pairs when the occupan-
cies are `accidentally' degenerate (usually, both  very
close  to 2.000...) within the numerical machine preci-
sion.  A warning message is printed when the core occu-
pancy is less than 1.9990, indicating a possible ``core
polarization'' effect of physical significance.

#IExcited State  Antibond  Labels.#N  The  program  now
directly investigates the nodal structure of an NBO (by
examining the overlap matrix in the PNHO basis)  before
assigning  it  a  label  as  a  ``bond'' (unstarred) or
``antibond''  (starred)  NBO.   In  previous  versions,
these labels were assigned on the basis of the presumed
higher occupancy  of  the  in-phase  bond  combination,
which was generally true for ground states, but not for
excited states.  The program now prints a warning  mes-
sage whenever it encounters the ``anomalous'' situation
of an out-of-phase antibond NBO having higher occupancy
than the corresponding in-phase bond NBO, indicative of
an excited-state configuration.  [WARNING: the  overlap
test  cannot  be applied to semi-empirical methods with
orthogonal AOs (e.g., AMPAC), so  antibond  labels  for
these methods are assigned, as in previous versions, on



                       July 11, 1995





                           - 11 -


the
basis of occupancy.]

#IAlternative Resonance Structures.#N The  program  now
institutes a search for alternative Lewis (`resonance')
structures when two or more structures may be  competi-
tive,  and  returns  the  structure of lowest non-Lewis
occupancy.  This  corrects  a  possible  dependence  on
atomic numbering in cases of strong delocalization.

Despite these changes and extensions, version  3.0  has
been  designed  to be upward compatible with v. 2.0, as
nearly as possible.  Previous users of NBO  2.0  should
find that their jobs run similarly (i.e., most keywords
continue to function as in previous  versions).   Thus,
experienced  NBO users should find little difficulty in
adapting to, and experimenting with, the new  capabili-
ties of the program.


#BA.2 INSTALLING THE NBO PROGRAM#N

0 The NBO programs and manual are provided on a distri-
bution  tape.   The  tape  contains  three  files:  the
TechSet code of this manual (file NBO.MAN), a file con-
taining  the  core  NBO  source routines and supporting
driver routines (file NBO.SRC), and the Fortran  ``ena-
bler'' program (file ENABLE.FOR).

0 In overview, the installation procedure involves  the
following  steps (the details of each step being depen-
dent on your operating system):

#IEnabling the NBO routines.#N  Copy  the  contents  of
the  distribution  tape  onto  your system.  Using your
system Fortran 77 compiler, compile and link  the  ena-
bler  program  to create the ENABLE.EXE executable; for
example, the VMS commands to create ENABLE.EXE are
 #T
     FOR ENABLE
     LINK ENABLE

#NNow,  run  the  ENABLE  program  (e.g.,  type   ``RUN
ENABLE'' in a VMS system), and answer the prompt
 #T
     NBO program version to enable?

#Nby selecting from the available offerings.  Each  ESS
package   is  associated  with  a  3-letter  identifier
(``G88'' for GAUSSIAN-88, ``GMS'' for  GAMESS,  ``AMP''
for  AMPAC,  etc.).   The  ENABLE program will create a
file #IXXX#NNBO.FOR (where `#IXXX#N' is the identifier)
that incorporates the appropriate drivers for your ESS.




                       July 11, 1995





                           - 12 -


#ICompiling the NBO routines.#N  Using your system For-
tran 77 compiler, compile the #IXXX#NNBO.FOR file to an
object  code  file  (say,  #IXXX#NNBO.OBJ).   [Compiler
errors  (if  any)  should  be  fixed before proceeding.
Please notify the authors if you encounter undue diffi-
culties in this step.]

#IModifying the ESS routines.#N  In  general,  the  ESS
source  Fortran  code  must be modified to call the NBO
routines near the point where the ESS performs Mulliken
Population  Analysis  or  evaluates  properties  of the
final wavefunction.  The  modification  generally  con-
sists  of  inserting  a  single statement (viz., ``CALL
RUNNBO'') in one subroutine of your  ESS  system.   See
the  appropriate  Appendix  of this Manual for detailed
information on exactly how to modify the ESS  code  for
your chosen system.

#IRebuilding the  integrated  ESS/NBO  program.#N   Re-
compile your modified ESS programs and link the result-
ing object file (say, ESS.OBJ) with the  #IXXX#NNBO.OBJ
file to form the final ESS.EXE executable.  In general,
this step will closely follow the initial  installation
procedure  for  your  ESS,  with the exception that the
#IXXX#NNBO.OBJ file must be included in the link state-
ment  (or deposited in one of the libraries accessed by
the linker, etc.).

Note that installation of the NBO  programs  into  your
ESS  system  in  no  way  affects  the  way your system
processes  standard  input  files.   The  only   change
involves  enabling  the  reading  of  NBO  keylists (if
detected in your input file), performance of the  tasks
requested  in the keylist, and return of control to the
parent ESS program in the state in which the  NBO  call
was encountered.

0 If you are interfacing the NBO programs to a new  ESS
package  (not  represented  in the driver routines pro-
vided with this distribution), see Section C  for  gui-
dance  on how to create drivers for your ESS to provide
the necessary information.  Alternatively, see  Section
B.7  for a description of the input file to GENNBO, the
stand-alone version of the NBO program.

0 The TechSet-coded version of  this  manual,  NBO.MAN,
can  be  printed  on  an  HP LaserJet printer (`F' car-
tridge) with the TECHSET technical typesetting  program
[ACS  Software,  American  Chemical  Society, Marketing
Communications  Dept.,  1155  Sixteenth  Street,  N.W.,
Washington, D.C. 20036].


#BA.3 TUTORIAL EXAMPLE FOR METHYLAMINE#N



                       July 11, 1995





                           - 13 -


#IA.3.1 Running the Example#N

0 This section provides an introductory  `quick  start'
tutorial  on  running a simple NBO job and interpreting
the output.  The example chosen is that of  methylamine
(CH#d3#uNH#d2#u)  in  Pople-Gordon  idealized geometry,
treated at the #Iab  initio#N  RHF/3-21G  level.   This
simple split-valence basis set consists of 28 AOs (nine
each on C and N, two on each H),  extended  by  13  AOs
beyond the minimal basis level.

0  Input  files  to  run  this  job  (or  its   nearest
equivalent)  with  each  ESS are given in the Appendix.
(The output shown below was  created  with  the  GAMESS
system.)   In  most  cases, you can modify the standard
ESS input file to produce NBO output by simply  includ-
ing the line
 #T
     $NBO $END

#Nat the end of the file.  This is an `empty' NBO keyl-
ist, specifying that NBO analysis should be carried out
at the #Idefault#N level.

0 The default NBO output produced by  this  example  is
shown  below,  just  as it appears in your output file.
The start of the NBO section is marked  by  a  standard
header and storage info:

*******************************************************************************
            N A T U R A L   A T O M I C   O R B I T A L
A N D
         N A T U R A L   B O N D   O R B I T A L   A  N
A          L          Y          S          I         S
*******************************************************************************

Job title:  Methylamine...RHF/3-21G//Pople-Gordon stan-
dard geometry

Storage needed:  2505 in NPA,  2569  in  NBO  (  750000
available)
 #T @seg


#NNote that all NBO output is formatted  to  a  maximum
80-character width for convenient display on a computer
terminal.  The NBO heading echoes  any  requested  key-
words  (none for the present default case) and shows an
estimate of the memory requirements (in  double  preci-
sion  words) for the separate steps of the NBO process,
compared  to  the  total  allocated  memory   available
through  your  ESS  process.  Increase the memory allo-
cated to your ESS process if the estimated NBO requests
exceed   the   available   storage.    #IA.3.2  Natural



                       July 11, 1995





                           - 14 -


Population
Analysis#N

#N0 The next four NBO  output  segments  summarize  the
results  of  natural  population  analysis  (NPA).  The
first segment is the main NAO table, as shown below:

NATURAL POPULATIONS:  Natural atomic  orbital  occupan-
cies

 NAO Atom #  lang   Type(AO)     Occupancy       Energy
----------
-----------------------------------------------
  1    C  1  s      Cor( 1s)     1.99900     -11.04184
  2    C  1  s      Val( 2s)     1.09038      -0.28186
  3    C  1  s      Ryd( 3s)     0.00068       1.95506
  4    C  1  px     Val( 2p)     0.89085      -0.01645
  5    C  1  px     Ryd( 3p)     0.00137       0.93125
  6    C  1  py     Val( 2p)     1.21211      -0.07191
  7    C  1  py     Ryd( 3p)     0.00068       1.03027
  8    C  1  pz     Val( 2p)     1.24514      -0.08862
  9    C  1  pz     Ryd( 3p)     0.00057       1.01801

 10    N  2  s      Cor( 1s)     1.99953     -15.25950
 11    N  2  s      Val( 2s)     1.42608      -0.71700
 12    N  2  s      Ryd( 3s)     0.00016       2.75771
 13    N  2  px     Val( 2p)     1.28262      -0.18042
 14    N  2  px     Ryd( 3p)     0.00109       1.57018
 15    N  2  py     Val( 2p)     1.83295      -0.33858
 16    N  2  py     Ryd( 3p)     0.00190       1.48447
 17    N  2  pz     Val( 2p)     1.35214      -0.19175
 18    N  2  pz     Ryd( 3p)     0.00069       1.59492

 19    H  3  s      Val( 1s)     0.81453       0.13283
 20    H  3  s      Ryd( 2s)     0.00177       0.95067

 21    H  4  s      Val( 1s)     0.78192       0.15354
 22    H  4  s      Ryd( 2s)     0.00096       0.94521

 23    H  5  s      Val( 1s)     0.78192       0.15354
 24    H  5  s      Ryd( 2s)     0.00096       0.94521

 25    H  6  s      Val( 1s)     0.63879       0.20572
 26    H  6  s      Ryd( 2s)     0.00122       0.99883

 27    H  7  s      Val( 1s)     0.63879       0.20572
 28    H  7  s      Ryd( 2s)     0.00122       0.99883
 #T
     @seg


          #NFor each of the 28  NAO  functions,  this  table
          lists  the  atom  to which NAO is attached (in the
          numbering scheme of the ESS program), the  angular



                       July 11, 1995





                           - 15 -


          momentum
          type `lang' (#Is#N, #Ip#dx#u#N, etc., in the coor-
          dinate  system  of  the  ESS program), the orbital
          type (whether core, valence,  or  Rydberg,  and  a
          conventional  hydrogenic-type  label), the orbital
          occupancy (number of electrons, or `natural  popu-
          lation'  of  the  orbital), and the orbital energy
          (in the favored units of the ESS program, in  this
          case atomic units: 1 a.u. = 627.5 kcal/mol).  [For
          example, NAO 4 (the highest energy  C  orbital  of
          the  NMB  set)  is  the  valence shell 2#Ip#N#dx#u
          orbital on carbon, occupied by  0.8909  electrons,
          whereas  NAO  5  is  a Rydberg 3#Ip#N#dx#u orbital
          with only 0.0014 electrons.]  Note that the  occu-
          pancies  of  the  Rydberg (Ryd) NAOs are typically
          much lower than  those  of  the  core  (Cor)  plus
          valence  (Val)  NAOs  of the natural minimum basis
          set, reflecting the dominant role of the NMB orbi-
          tals in describing molecular properties.

          0 The principal quantum numbers for the NAO labels
          (1#Is#N, 2#Is#N, 3#Is#N, etc.) are assigned on the
          basis of the energy order  if  a  Fock  matrix  is
          available, or on the basis of occupancy otherwise.
          A message is  printed  warning  of  a  `population
          inversion' if the occupancy and energy ordering do
          not coincide.

Summary of Natural Population Analysis:

                                      Natural Population
              Natural                              ---------
--------------------------------------
   Atom #      Charge         Core       Valence     Rydberg
Total                                             ----------
-------------------------------------------------------------
     C   1    -0.44079       1.99900      4.43848    0.00331
6.44079
     N  2    -0.89715       1.99953      5.89378     0.00384
7.89715
     H  3     0.18370       0.00000      0.81453     0.00177
0.81630
     H  4     0.21713       0.00000      0.78192     0.00096
0.78287
     H  5     0.21713       0.00000      0.78192     0.00096
0.78287
     H  6     0.35999       0.00000      0.63879     0.00122
0.64001
     H  7     0.35999       0.00000      0.63879     0.00122
0.64001
=======================================================================
  *  Total  *   0.00000       3.99853    13.98820    0.01328
18.00000




                       July 11, 1995





                           - 16 -


#NThe next segment is an atomic summary showing the  natural
atomic  charges (nuclear charge minus summed natural popula-
tions of NAOs on the atom) and total core, valence, and Ryd-
berg populations on each atom:

 #T
     @seg


          #NThis table succinctly  describes  the  molecular
          charge distribution in terms of NPA charges.  [For
          example,  the  carbon  atom  of   methylamine   is
          assigned  a  net NPA charge of minus 0.441 at this
          level; note also the slightly less positive charge
          on  H(3)  than  on the other two methyl hydrogens:
          +0.184 vs. +0.217.]
                                Natural Population  --------
------------------------------------------------
  Core                       3.99853 ( 99.9632% of   4)
  Valence                   13.98820 ( 99.9157% of  14)
  Natural Minimal Basis     17.98672 ( 99.9262% of  18)
  Natural Rydberg Basis      0.01328 (  0.0738% of  18)  ---
-----------------------------------------------------

#NNext follows a summary of the NMB and NRB populations  for
the composite system, summed over atoms:

 #T @seg


#NThis exhibits the high percentage contribution (typically,
>  99%) of the NMB set to the molecular charge distribution.
[In the present case, for example, the 13  Rydberg  orbitals
of  the  NRB  set contribute only 0.07% of the electron den-
sity, whereas the 15 NMB functions account for 99.93% of the
total.]

#NFinally, the natural  populations  are  summarized  as  an
effective valence electron configuration (``natural electron
configuration'') for each atom:
   Atom #          Natural Electron Configuration  ---------
-
------------------------------------------------------------------
     C  1      [core]2s( 1.09)2p( 3.35)
     N  2      [core]2s( 1.43)2p( 4.47)
     H  3            1s( 0.81)
     H  4            1s( 0.78)
     H  5            1s( 0.78)
     H  6            1s( 0.64)
     H  7            1s( 0.64)


 #T
     @seg



                       July 11, 1995





                           - 17 -


          #NAlthough the occupancies of the atomic  orbitals
          are  non-integer in the molecular environment, the
          effective atomic configurations can be related  to
          idealized  atomic  states in `promoted' configura-
          tions.  [For example, the carbon atom in the above
          table  is  most  nearly  described by an idealized
          1s#u2#d2s#u1#d2p#u3#d electron configuration.]


          #IA.3.3 Natural Bond Orbital Analysis#N

          #N0 The next segments of the output summarize  the
          results   of  NBO  analysis.   The  first  segment
          reports on  details  of  the  search  for  an  NBO
          natural Lewis structure:

NATURAL BOND ORBITAL ANALYSIS:

                      Occupancies         Lewis    Structure
Low   High
          Occ.      -------------------    -----------------
occ   occ
 Cycle   Thresh.   Lewis    Non-Lewis      CR   BD   3C   LP
(L)                         (NL)                         Dev
=============================================================================
  1(1)     1.90     17.95048    0.04952       2    6   0   1
0                 0               0.02            ----------
-------------------------------------------------------------------

Structure accepted: No low occupancy Lewis orbitals
 #T @seg


#NNormally, there is but one cycle of the  NBO  search  (cf.
the  ``RESONANCE''  keyword, Section B.6.6).  The table sum-
marizes a variety of information for each cycle:  the  occu-
pancy  thresh#|old  for a `good' pair in the NBO search; the
total populations of Lewis and non-Lewis NBOs; the number of
core  (CR), 2-center bond (BD), 3-center bond (3C), and lone
pair (LP) NBOs in the natural Lewis structure; the number of
low-occupancy  Lewis  (L) and `high-occupancy' (> 0.1e) non-
Lewis (NL) orbitals; and the maximum  deviation  (`Dev')  of
any  formal  bond  order from a nominal estimate (NAO Wiberg
bond index) for the structure.  [If the latter exceeds  0.1,
additional  NBO  searches  are  initiated  (indicated by the
parenthesized number under `Cycle')  for  alternative  Lewis
structures.]   The  Lewis structure is accepted if all orbi-
tals of the formal  Lewis  structure  exceed  the  occupancy
thresh#|old (default, 1.90 electrons).

0 #NNext follows a more detailed breakdown of the Lewis  and
non-Lewis  occupancies into core, valence, and Rydberg shell
contributions:
WARNING:  1 low occupancy (<1.9990e) core orbital  found  on



                       July 11, 1995





                           - 18 -


C
1

--------------------------------------------------------
  Core                      3.99853 ( 99.963% of   4)
  Valence Lewis            13.95195 ( 99.657% of  14)
 ==================       ============================
  Total Lewis              17.95048 ( 99.725% of  18)
 -----------------------------------------------------
  Valence non-Lewis         0.03977 (  0.221% of  18)
  Rydberg non-Lewis         0.00975 (  0.054% of  18)
 ==================       ============================
  Total non-Lewis           0.04952 (  0.275% of  18)  -----
---------------------------------------------------

 #T @seg


#NThis shows the general quality of the natural Lewis struc-
ture  description  in  terms  of the percentage of the total
electron density (e.g., in the  above  case,  about  99.7%).
The table also exhibits the relatively important role of the
valence non-Lewis orbitals (i.e., the six valence antibonds,
NBOs  23-28)  relative to the extra-valence orbitals (the 13
Rydberg NBOs 10-22) in the slight departures from  a  local-
ized  Lewis  structure model.  (In this case, the table also
includes a warning about a carbon core orbital with slightly
less than double occupancy.)

    (Occupancy)   Bond orbital/ Coefficients/ Hybrids  -----
-----
---------------------------------------------------------------------
  1. (1.99858) BD ( 1) C 1- N 2
               ( 40.07%)   0.6330* C  1  s(  21.71%)p  3.61(
78.29%)
                                       -0.0003       -0.4653
-0.0238 -0.8808 -0.0291
                                       -0.0786       -0.0110
0.0000  0.0000
               ( 59.93%)   0.7742* N  2  s(  30.88%)p  2.24(
69.12%)
                                       -0.0001       -0.5557
0.0011  0.8302  0.0004
                                        0.0443       -0.0098
0.0000  0.0000
  2. (1.99860) BD ( 1) C 1- H 3
               ( 59.71%)   0.7727* C  1  s(  25.78%)p  2.88(
74.22%)
                                       -0.0002       -0.5077
0.0069  0.1928  0.0098
                                        0.8396       -0.0046
0.0000  0.0000
               ( 40.29%)   0.6347* H 3 s(100.00%)
                                       -1.0000 -0.0030



                       July 11, 1995





                           - 19 -


3. (1.99399) BD ( 1) C 1- H 4
               ( 61.02%)   0.7812* C  1  s(  26.28%)p  2.80(
73.72%)
                                        0.0001        0.5127
-0.0038 -0.3046 -0.0015
                                        0.3800       -0.0017
0.7070 -0.0103
               ( 38.98%)   0.6243* H 4 s(100.00%)
                                        1.0000  0.0008
  4. (1.99399) BD ( 1) C 1- H 5
               ( 61.02%)   0.7812* C  1  s(  26.28%)p  2.80(
73.72%)
                                        0.0001        0.5127
-0.0038 -0.3046 -0.0015
                                        0.3800       -0.0017
-0.7070  0.0103
               ( 38.98%)   0.6243* H 5 s(100.00%)
                                        1.0000  0.0008
  5. (1.99442) BD ( 1) N 2- H 6
               ( 68.12%)   0.8253* N  2  s(  25.62%)p  2.90(
74.38%)
                                        0.0000        0.5062
0.0005  0.3571  0.0171
                                       -0.3405        0.0069
-0.7070 -0.0093
               ( 31.88%)   0.5646* H 6 s(100.00%)
                                        1.0000  0.0020
  6. (1.99442) BD ( 1) N 2- H 7
               ( 68.12%)   0.8253* N  2  s(  25.62%)p  2.90(
74.38%)
                                        0.0000        0.5062
0.0005  0.3571  0.0171
                                       -0.3405        0.0069
0.7070  0.0093
               ( 31.88%)   0.5646* H 7 s(100.00%)
                                        1.0000  0.0020
  7. (1.99900) CR ( 1)  C  1              s(100.00%)p  0.00(
0.00%)
                                        1.0000       -0.0003
0.0000 -0.0002  0.0000
                                        0.0001        0.0000
0.0000  0.0000
  8. (1.99953) CR ( 1)  N  2              s(100.00%)p  0.00(
0.00%)
                                        1.0000       -0.0001
0.0000  0.0001  0.0000
                                        0.0000        0.0000
0.0000  0.0000
  9. (1.97795) LP ( 1) N  2              s(  17.85%)p  4.60(
82.15%)
                                        0.0000        0.4225
0.0002  0.2360 -0.0027
                                        0.8749       -0.0162
0.0000  0.0000



                       July 11, 1995





                           - 20 -


10. (0.00105) RY*(  1)  C  1              s(   1.57%)p62.84(
98.43%)
                                        0.0000       -0.0095
0.1248 -0.0305  0.7302
                                       -0.0046        0.6710
0.0000  0.0000
 11.  (0.00034)  RY*(  2)  C   1               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0146  0.9999
 12. (0.00022) RY*( 3) C  1              s(  56.51%)p  0.77(
43.49%)
                                        0.0000       -0.0023
0.7517 -0.0237  0.3710
                                       -0.0094       -0.5447
0.0000  0.0000
 13. (0.00002) RY*( 4) C  1              s(  41.87%)p  1.39(
58.13%)
 14. (0.00116) RY*( 1)  N  2              s(   1.50%)p65.53(
98.50%)
                                        0.0000       -0.0062
0.1224  0.0063  0.0371
                                        0.0197        0.9915
0.0000  0.0000
 15.  (0.00044)  RY*(  2)  N   2               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
-0.0132  0.9999
 16. (0.00038) RY*( 3) N  2              s(  33.38%)p  2.00(
66.62%)
                                        0.0000        0.0133
0.5776  0.0087 -0.8150
                                       -0.0121       -0.0405
0.0000  0.0000
 17. (0.00002) RY*( 4) N  2              s(  65.14%)p  0.54(
34.86%)
 18. (0.00178) RY*( 1) H 3             s(100.00%)
                                       -0.0030  1.0000
 19. (0.00096) RY*( 1) H 4             s(100.00%)
                                       -0.0008  1.0000
 20. (0.00096) RY*( 1) H 5             s(100.00%)
                                       -0.0008  1.0000
 21. (0.00122) RY*( 1) H 6             s(100.00%)
                                       -0.0020  1.0000
 22. (0.00122) RY*( 1) H 7             s(100.00%)
                                       -0.0020  1.0000
 23. (0.00016) BD*( 1) C 1- N 2
               ( 59.93%)   0.7742* C  1  s(  21.71%)p  3.61(
78.29%)
                                       -0.0003       -0.4653



                       July 11, 1995





                           - 21 -


-0.0238
-0.8808 -0.0291
                                       -0.0786       -0.0110
0.0000  0.0000
               ( 40.07%)  -0.6330* N  2  s(  30.88%)p  2.24(
69.12%)
                                       -0.0001       -0.5557
0.0011  0.8302  0.0004
                                        0.0443       -0.0098
0.0000  0.0000
 24. (0.01569) BD*( 1) C 1- H 3
               ( 40.29%)   0.6347* C  1  s(  25.78%)p  2.88(
74.22%)
                                        0.0002        0.5077
-0.0069 -0.1928 -0.0098
                                       -0.8396        0.0046
0.0000  0.0000
               ( 59.71%)  -0.7727* H 3 s(100.00%)
                                        1.0000  0.0030
 25. (0.00769) BD*( 1) C 1- H 4
               ( 38.98%)   0.6243* C  1  s(  26.28%)p  2.80(
73.72%)
                                       -0.0001       -0.5127
0.0038  0.3046  0.0015
                                       -0.3800        0.0017
-0.7070  0.0103
               ( 61.02%)  -0.7812* H 4 s(100.00%)
                                       -1.0000 -0.0008
 26. (0.00769) BD*( 1) C 1- H 5
               ( 38.98%)   0.6243* C  1  s(  26.28%)p  2.80(
73.72%)
                                       -0.0001       -0.5127
0.0038  0.3046  0.0015
                                       -0.3800        0.0017
0.7070 -0.0103
               ( 61.02%)  -0.7812* H 5 s(100.00%)
                                       -1.0000 -0.0008
 27. (0.00426) BD*( 1) N 2- H 6
               ( 31.88%)   0.5646* N  2  s(  25.62%)p  2.90(
74.38%)
                                        0.0000       -0.5062
-0.0005 -0.3571 -0.0171
                                        0.3405       -0.0069
0.7070  0.0093
               ( 68.12%)  -0.8253* H 6 s(100.00%)
                                       -1.0000 -0.0020
 28. (0.00426) BD*( 1) N 2- H 7
               ( 31.88%)   0.5646* N  2  s(  25.62%)p  2.90(
74.38%)
                                        0.0000       -0.5062
-0.0005 -0.3571 -0.0171
                                        0.3405       -0.0069
-0.7070 -0.0093
               ( 68.12%)  -0.8253* H 7 s(100.00%)



                       July 11, 1995





                           - 22 -


-1.0000 -0.0020

#NNext follows the main listing of NBOs, displaying the form
and  occupancy  of  the  complete  set of NBOs that span the
input AO space:
 #T


@seg


#NFor each NBO (1-28), the first line of printout shows  the
occupancy  (between 0 and 2.0000 electrons) and unique label
of the NBO.  This label gives the type (``BD'' for  2-center
bond,  ``CR''  for  1-center  core pair, ``LP'' for 1-center
valence lone pair, ``RY*'' for 1-center Rydberg, and ``BD*''
for  2-center  antibond,  the  unstarred  and starred labels
corresponding to Lewis and non-Lewis NBOs, respectively),  a
serial  number  (1,  2,...  if there is a single, double,...
bond between the pair of atoms), and the  atom(s)  to  which
the NBO is affixed.  [For example, the first NBO in the sam-
ple output is the  2-center bond  (with  1.99858  electrons)
between  carbon  (atom  1)  and  nitrogen  (atom 2), the gma
#dCN#u bond.]  The next lines summarize the  natural  atomic
hybrids  #Ih#N#dA#u of which the NBO is composed, giving the
percentage (100|#Ic#N#dA#u|#u2#d) of the NBO on each  hybrid
(in  parentheses),  the polarization coefficient #Ic#N#dA#u,
the atom label, and a hybrid label showing the  #Isp#N#u  #d
composition  (percentage  #Is#N-character,  #Ip#N-character,
etc.) of each #Ih#N#dA#u.  [For example, the gma #dCN#u  NBO
is  formed  from  an  #Isp#N#u3.61#d  hybrid  (78.3%  #Ip#N-
character) on  carbon  interacting  with  an  #Isp#N#u2.24#d
hybrid (69.1% #Ip#N-character) on nitrogen,

gma     #dCN#u      =      0.633(#Isp#N#u3.61#d)#dC#u      +
0.774(#Isp#N#u2.24#d)#dN#u

corresponding  roughly  to  the   qualitative   concept   of
interacting  #Isp#N#u3#d  hybrids  (75% #Ip#N-character) and
the higher electronegativity  (larger  polarization  coeffi-
cient)  of  N.]   Below each NHO label is the set of coeffi-
cients that specify how the NHO is written explicitly  as  a
linear  combination  of  NAOs on the atom.  The order of NAO
coefficients follows the numbering of the NAO tables.   [For
example,   in   the  first  NBO  entry,  the  carbon  hybrid
#Ih#N#dC#u of the gma #dCN#u bond has  largest  coefficients
for  the  2#und#d  and  4#uth#d  NAOs,  corresponding to the
approximate description

#Ih#N#dC#u    ~=     minus     0.4653(2#Is#N)#dC#u     minus
0.8808(2#Ip#N#dx#u)#dC#u

in terms of the valence NAOs of the carbon  atom.]   In  the
CH#d3#uNH#d2#u  example,  the  NBO search finds the C-N bond



                       July 11, 1995





                           - 23 -


(NBO
1), three C-H bonds (NBOs 2, 3, 4), two N-H bonds  (NBOs  5,
6),  N lone pair (NBO 9), and C and N core pairs (NBOs 7, 8)
of the expected Lewis structure.  NBOs 10-28  represent  the
residual  non-Lewis NBOs of low occupancy.  In this example,
it is also interesting to note the slight asymmetry  of  the
three  gma  #dCH#u  NBOs,  and the slightly higher occupancy
(0.01569   #Ivs.#N   0.0077   electrons)    in    the    gma
*#<#dC#d1#uH#d3#u#u antibond (NBO 24) lying #Itrans#N to the
nitrogen lone pair.  #IA.3.4 NHO Directional Analysis#N

0 The next segment of output summarizes the angular  proper-
ties of the natural hybrid orbitals:

NHO Directionality and "Bond Bending" (deviations from  line
of nuclear centers)

        [Thresholds for printing:  angular deviation  >  1.0
degree]
                                   hybrid   p-character    >
25.0%
                                   orbital   occupancy     >
0.10e

                      Line  of   Centers          Hybrid   1
Hybrid 2
                      ---------------    -------------------
------------------
          NBO           Theta   Phi     Theta    Phi     Dev
Theta                        Phi                         Dev
===============================================================================
  1.  BD  (  1)  C 1- N 2    90.0    5.4     --     --    --
90.0  182.4   3.0
  3. BD ( 1) C 1- H 4    35.3  130.7     34.9   129.0    1.0
--     --    --
  4. BD ( 1) C 1- H 5   144.7  130.7    145.1   129.0    1.0
--     --    --
  5. BD ( 1) N 2- H 6   144.7  310.7    145.0   318.3    4.4
--     --    --
  6. BD ( 1) N 2- H 7    35.3  310.7     35.0   318.3    4.4
--     --    --
  9. LP ( 1) N 2          --      --      90.0    74.8    --
--     --    --

 #T @seg


#NThe `direction' of a hybrid is specified in terms  of  the
polar       (heta       )       and       azimuthal      (hi
) angles (in  the  ESS  coordinate  system)  of  the  vector
describing  its  #Ip#N-component.   The  hybrid direction is
compared with the direction of the line of  centers  between
the  two  nuclei  to  determine  the  `bending' of the bond,
expressed as  the  deviation  angle  (``Dev,''  in  degrees)



                       July 11, 1995





                           - 24 -


between
these two directions.  For example,  in  the  CH#d3#uNH#d2#u
case  shown  above,  the nitrogen NHO of the gma #dCN#u bond
(NBO 1) is bent  away  from  the  line  of  C-N  centers  by
3.09egree  ,  whereas the carbon NHO is approximately aligned
with the C-N axis (within the 1.09egree  threshold for print-
ing).   The  N-H  bonds  (NBOs  5,  6) are bent even further
(4.49egree ).  The information in this table is often  useful
in  anticipating the direction of geometry changes resulting
from geometry optimization (viz., likely reduced pyramidali-
zation  of  the  -NH#d2#u group to relieve the nitrogen bond
`kinks' found in the tetrahedral Pople-Gordon geometry).


#IA.3.5 Perturbation Theory Energy Analysis#N

0 The next segment summarizes the second-order  perturbative
estimates  of  `donor-acceptor' (bond-antibond) interactions
in the NBO basis:
Second Order Perturbation Theory Analysis of Fock Matrix  in
NBO Basis

    Threshold for printing:   0.50 kcal/mol
                                                         E(2)
E(j)-E(i) F(i,j)
     Donor   NBO   (i)                Acceptor    NBO    (j)
kcal/mol                      a.u.                      a.u.
===============================================================================

within unit  1
  2.  BD  (  1)  C  1-  H  3      /  14.   RY*(   1)   N   2
0.84    2.18    0.038
  3. BD ( 1)  C  1-  H  4      /  26.  BD*(  1)  C  1-  H  5
0.52    1.39    0.024
  3. BD ( 1)  C  1-  H  4      /  27.  BD*(  1)  N  2-  H  6
3.03    1.37    0.057
  4. BD ( 1)  C  1-  H  5      /  25.  BD*(  1)  C  1-  H  4
0.52    1.39    0.024
  4. BD ( 1)  C  1-  H  5      /  28.  BD*(  1)  N  2-  H  7
3.03    1.37    0.057
  5.  BD  (  1)  N  2-  H  6      /  10.   RY*(   1)   C   1
0.56    1.78    0.028
  5. BD ( 1)  N  2-  H  6      /  25.  BD*(  1)  C  1-  H  4
2.85    1.51    0.059
  6.  BD  (  1)  N  2-  H  7      /  10.   RY*(   1)   C   1
0.56    1.78    0.028
  6. BD ( 1)  N  2-  H  7      /  26.  BD*(  1)  C  1-  H  5
2.85    1.51    0.059
  7.  CR  (  1)  C  1            /   16.   RY*(   3)   N   2
0.61   13.11    0.080
  7.  CR  (  1)  C  1            /   18.   RY*(   1)   H   3
1.40   11.99    0.116
  7.  CR  (  1)  C  1            /   19.   RY*(   1)   H   4
1.55   11.99    0.122



                       July 11, 1995





                           - 25 -


7. CR ( 1) C 1          / 20. RY*( 1) H 5               1.55
11.99    0.122
  8.  CR  (  1)  N  2            /   10.   RY*(   1)   C   1
1.51   16.23    0.140
  8.  CR  (  1)  N  2            /   12.   RY*(   3)   C   1
0.84   16.77    0.106
  8.  CR  (  1)  N  2            /   21.   RY*(   1)   H   6
0.61   16.26    0.089
  8.  CR  (  1)  N  2            /   22.   RY*(   1)   H   7
0.61   16.26    0.089
  9. LP  (  1)  N  2           /  24.  BD*(  1)  C  1-  H  3
8.13    1.13    0.086
  9. LP  (  1)  N  2           /  25.  BD*(  1)  C  1-  H  4
1.46    1.14    0.037
  9. LP  (  1)  N  2           /  26.  BD*(  1)  C  1-  H  5
1.46    1.14    0.037

 #T @seg


#NThis is carried out by examining all possible interactions
between `filled' (donor) Lewis-type NBOs and `empty' (accep-
tor) non-Lewis NBOs, and estimating their  energetic  impor-
tance   by   2nd-order  perturbation  theory.   Since  these
interactions lead to loss of occupancy  from  the  localized
NBOs  of  the  idealized Lewis structure into the empty non-
Lewis orbitals (and thus, to departures from  the  idealized
Lewis structure description), they are referred to as `delo-
calization' corrections to the  zeroth-order  natural  Lewis
structure.   For  each  donor  NBO  (#Ii#N) and acceptor NBO
(#Ij#N), the stabilization energy E(2) associated with delo-
calization  (``2e-stabilization'') #Ii7 arr  j#N is estimated
as

E(2) = Delta E#dij#u = q#di#u quo <>

where #Iq#N#di#u is the  donor  orbital  occupancy,  \psilon
#di#u,  \psilon  #dj#u  are diagonal elements (orbital ener-
gies) and F(i,j) is the off-diagonal NBO  Fock  matrix  ele-
ment.   [In  the  example  above,  the  #In#N#dN#u7  arr  gma
*#<#dCH#u interaction between the nitrogen lone pair (NBO 8)
and  the  antiperiplanar  C#d1#u-H#d3#u antibond (NBO 24) is
seen to give the strongest  stabilization,  8.13  kcal/mol.]
As the heading indicates, entries are included in this table
only when the interaction energy exceeds a default threshold
of 0.5 kcal/mol.  #IA.3.6 NBO Summary#N

0 Next appears a condensed summary of  the  principal  NBOs,
showing  the  occupancy, orbital energy, and the qualitative
pattern of delocalization interactions associated with each:
Natural Bond Orbitals (Summary):

                                                    Princi-
pal Delocalizations



                       July 11, 1995





                           - 26 -


NBO                          Occupancy                Energy
(geminal,vicinal,remote)
===============================================================================
Molecular unit  1  (CH5N)
  1. BD ( 1) C 1- N 2       1.99858    -0.89908
  2. BD ( 1) C 1- H 3       1.99860    -0.69181    14(v)
  3.  BD  (  1)  C  1-   H   4         1.99399      -0.68892
27(v),26(g)
  4.  BD  (  1)  C  1-   H   5         1.99399      -0.68892
28(v),25(g)
  5.  BD  (  1)  N  2-   H   6         1.99442      -0.80951
25(v),10(v)
  6.  BD  (  1)  N  2-   H   7         1.99442      -0.80951
26(v),10(v)
  7.  CR   (   1)   C   1              1.99900     -11.04131
19(v),20(v),18(v),16(v)
  8.  CR   (   1)   N   2              1.99953     -15.25927
10(v),12(v),21(v),22(v)
  9.  LP   (   1)   N   2              1.97795      -0.44592
24(v),25(v),26(v)
 10. RY*( 1) C 1            0.00105     0.97105
 11. RY*( 2) C 1            0.00034     1.02120
 12. RY*( 3) C 1            0.00022     1.51414
 13. RY*( 4) C 1            0.00002     1.42223
 14. RY*( 1) N 2            0.00116     1.48790
 15. RY*( 2) N 2            0.00044     1.59323
 16. RY*( 3) N 2            0.00038     2.06475
 17. RY*( 4) N 2            0.00002     2.25932
 18. RY*( 1) H 3            0.00178     0.94860
 19. RY*( 1) H 4            0.00096     0.94464
 20. RY*( 1) H 5            0.00096     0.94464
 21. RY*( 1) H 6            0.00122     0.99735
 22. RY*( 1) H 7            0.00122     0.99735
 23. BD*( 1) C 1- N 2       0.00016     0.57000
 24. BD*( 1) C 1- H 3       0.01569     0.68735
 25. BD*( 1) C 1- H 4       0.00769     0.69640
 26. BD*( 1) C 1- H 5       0.00769     0.69640
 27. BD*( 1) N 2- H 6       0.00426     0.68086
 28. BD*( 1) N 2- H 7       0.00426     0.68086
      -------------------------------
             Total Lewis   17.95048  ( 99.7249%)
       Valence non-Lewis    0.03977  (  0.2209%)
       Rydberg non-Lewis    0.00975  (  0.0542%)
      -------------------------------
           Total unit  1   18.00000  (100.0000%)
          Charge unit  1    0.00000

 #T @seg


#NThis table allows one to quickly  identify  the  principal
delocalizing  acceptor  orbitals  associated with each donor
NBO, and their topological relationship to this  NBO,  i.e.,
whether  attached  to  the same atom (geminal, ``g''), to an



                       July 11, 1995





                           - 27 -


adjacent
bonded atom (vicinal, ``v''), or to a  more  remote  (``r'')
site.   These acceptor NBOs will generally correspond to the
principal `delocalization tails' of the NLMO associated with
the parent donor NBO.  [For example, in the table above, the
nitrogen lone pair  (NBO  9)  is  seen  to  be  the  lowest-
occupancy  (1.97795  electrons)  and  highest-energy  (minus
0.44592 a.u.) Lewis NBO, and  to  be  primarily  delocalized
into  antibonds 24, 25, 26 (the vicinal gma *#<#dCH#u NBOs).
The summary at the bottom of the table shows that the  Lewis
NBOs 1-9 describe about 99.7% of the total electron density,
with the remaining non-Lewis density found primarily in  the
valence-shell antibonds (particularly, NBO 24).]






#HSection B: NBO USER'S GUIDE#N


#BB.1  INTRODUCTION  TO  THE  NBO  USER'S  GUIDE   AND   NBO
KEYLISTS#N

0 Section B constitutes the general user's guide to the  NBO
program.   It  assumes  that the user has an installed elec-
tronic structure system (ESS) with attached NBO  program,  a
general  idea  of  what  the  NBO  method is about, and some
acquaintance with standard NBO terminology and output  data.
If  you  are  completely  inexperienced in these areas, read
Section A (General Introduction and  Installation)  for  the
necessary background to this Section.

0 The User's Guide describes how to use the NBO  program  by
modifying your input file to the ESS program to get some NBO
output.  The modification  consists  of  adding  a  list  of
#Ikeywords#N  in a prescribed #Ikeylist#N format.  Four dis-
tinct keylist ($KEY)  types  are  recognized  ($NBO,  $CORE,
$CHOOSE,  and  $DEL), and these will be described in turn in
Sections B.2-B.5.  Some of  the  details  of  inserting  NBO
keylists  into  the input file depend on the details of your
ESS method, and are described in  the  appropriate  Appendix
for  the ESS.  However, the general form of NBO keylists and
the meaning and function of each keyword are  identical  for
all  versions  (insofar  as the option is meaningful for the
ESS), and are described herein.

0 The four keylist types have common rules of syntax:  Keyl-
ist delimiters are identified by a ``$'' prefix.  Each keyl-
ist begins with the parent keylist  name  (e.g.,  ``$NBO''),
followed  by any number of keywords, and ended with the word
``$END''; for example,
 #T



                       July 11, 1995





                           - 28 -


$NBO   keyword1   keyword2   . . .   $END      !comment

#N(The allowed keyword entries for each type of keylist  are
described  in Sections B.2-B.5.)  The keylist is ``free for-
mat,'' with keywords separated by commas or  any  number  of
spaces.   An NBO option is activated by simply including its
keyword in the appropriate keylist.  The order  of  keywords
in  the principal $NBO keylist does not matter, but multiple
keylists must be given in the order (1) $NBO, (2) $CORE, (3)
$CHOOSE, (4) $DEL of presentation in Sections B.2-B.5.  Key-
words may be typed in upper  or  lower  case,  and  will  be
echoed  near  the top of the NBO output.  A $KEY list can be
continued to any number of lines, but all the entries  of  a
$KEY  list  must appear in a distinct set of lines, starting
with the $KEY name on the first line  and  ending  with  the
closing  $END  on  the  last  line  (i.e., no two $KEY lists
should share parts of the same line).  As the above  example
indicates,  any line in the keylist input may terminate with
an exclamation point  (!)  followed  by  `comment'  of  your
choice;  the  ``!'' is considered to terminate the line, and
the trailing `comment' is ignored by the program.


#BB.2 THE $NBO KEYLIST#N

#IB.2.1 Overview of $NBO keywords#N

0 The $NBO keylist is the principal means of specifying  NBO
job  options  and  controlling  output, and must precede any
other keylist ($CORE, $CHOOSE, or $DEL) in your input  file.
The  allowed  keywords that can appear in a $NBO keylist are
grouped as follows:

#IJob Control Keywords:#N #IJob Threshold Keywords:#N  #IMa-
trix  Output  Keywords:#N #IOther Output Control Keywords:#N
#IPrint Level Control:#N PRINT=n

Keywords are first listed and described according  to  these
formal  groupings  in  Sections  B.2.2-B.2.6.   Section  B.6
illustrates the effect of commonly used  $NBO  keywords  (as
well  as  other  $KEY  lists)  on  the  successive stages of
NAO/NBO/NLMO transformation and subsequent energy or  dipole
analysis, with sample output for these keyword options.

0 Some keywords of  the  $NBO  keylist  require  (or  allow)
numerical  values or other parameters to specify their exact
function.  In this case, the numerical  value  or  parameter
must  immediately follow the keyword after an equal sign (=)
or any number of blank spaces.  Examples:
 #T
     E2PERT=2.5   LFNPR 16  NBOMO=W25

#N(The equal sign is recommended, and will be  used  in  the
remaining examples.)



                       July 11, 1995





                           - 29 -


[0 Although the general user's interaction with the NBO pro-
grams is usually through the documented keywords of Sections
B.2.2-B.2.6, some additional `semi-documented' keywords  are
listed in Section B.2.7 which may be of interest to the spe-
cialist.] #IB.2.2 Job Control Keywords#N

0 The keywords in this group activate  or  deactivate  basic
tasks to be performed by the NBO programs, or change the way
the NBO search is conducted.  Each keyword is  described  in
terms  of  the option it activates (together with an indica-
tion of where the option is useful):

#IOPTION DESCRIPTION#N

Request Natural Population Analysis and printing of NPA sum-
mary  tables  (Section  A.3.2).  This keyword also activates
calculation of NAOs, except for semi-empirical ESS methods.

Request calculation of NBOs and printing  of  the  main  NBO
table (Section A.3.3).

Request printing of the NBO summary table  (Section  A.3.6).
This  combines  elements of the NBO table and 2nd-order per-
turbation theory analysis table (see below) in a  convenient
form for recognizing the principal delocalization patterns.

Request search for highly  delocalized  structures  (Section
B.6.6).   The  NBO  search  normally aborts when one or more
Lewis NBOs has less than the default occupancy threshold  of
1.90  electrons  for a `good' electron pair.  When the RESO-
NANCE keyword is activated, this threshold  is  successively
lowered  in  0.10  decrements  to  1.50,  and the NBO search
repeated to find the best Lewis structure within each  occu-
pancy  threshold.  The program returns with the best overall
Lewis structure (lowest total non-Lewis occupancy) found  in
these  searches.  (Useful for benzene and other highly delo-
calized molecules.)

Request that no bonds (2-center NBOs) are to  be  formed  in
the  NBO procedure (Section B.6.7).  The resulting NBOs will
then simply be 1-center atomic hybrids.  (Useful for  highly
ionic species.)

Request search for 3-center bonds (Section B.6.8).  The nor-
mal  default  is  to  search  for only 1- and 2-center NBOs.
(Useful for diborane and other electron-deficient  `bridged'
species.)

Skip the computation of NBOs, i.e., only determine NAOs  and
perform  natural population analysis.  (Useful when only NPA
is desired.)

Compute and print out the summary table of Natural Localized
Molecular  Orbitals  (Section  B.6.2).  NLMOs are similar to



                       July 11, 1995





                           - 30 -


Boys
or Edmiston-Ruedenberg LMOs,  but  more  efficiently  calcu-
lated.   (Useful  for `semi-localized' description of an SCF
or correlated wavefunction.)  Activated automatically by all
keywords  that  pertain  to  NLMOs  (e.g.,  AONLMO,  SPNLMO,
DIPOLE).


Note that the SKIPBO  keyword  has  higher  precedence  than
other  keywords in this list, so that keywords with which it
is implicitly in conflict (e.g., NBO, 3CBOND, NLMO) will  be
ignored  if SKIPBO is included in the $NBO keylist.  #IB.2.3
Job Threshold Keywords#N

0 The keywords in this group also activate new tasks  to  be
performed  by  the  NBO  program,  but these keywords may be
modified by one or more parameters (thresholds) that control
the  precise action to be taken.  (In each case the keywords
may also be used without parameters, accepting  the  default
values [in brackets].)

#IOPTION DESCRIPTION#N

Request the NHO Directional Analysis table (Section  A.3.4).
The three parameters [and default values] have the following
significance:

=  threshold angular deviation  for  printing  =   threshold
percentage  #Ip#N-character  for  printing  =  threshold NBO
occupancy for printing

#NParameter values may be separated by a space or a comma.

  Example:#T     BEND=2,10,1.9

#NThis example specifies that the bond-bending table  should
only  include  entries  for  angular  deviations of at least
29egree  (ang),  hybrids  of  at  least  10%  #Ip#N-character
(pct), and NBOs of occupancy at least 1.9 electrons (occ).

Request the Perturbation Theory Energy Analysis table  (Sec-
tion A.3.5), where

=  threshold energy (in kcal/mol) for printing

Entries will be printed for NBO  donor-acceptor  interaction
energies that exceed the `eval' threshold.

  Example:#T     E2PERT=5.0

#NThis example would print only interactions of at  least  5
kcal/mol  (i.e., only the single entry for the 8.13 kcal/mol
#In#N#dN#u7 arr  gma *#<#dCH#u interaction in the  output  of
Section A.3.5).



                       July 11, 1995





                           - 31 -


Request the Molecular Dipole Moment Analysis table  (Section
B.6.3), where

= threshold dipole moment (Debye) for printing

The program will carry out  a  decomposition  of  the  total
molecular  dipole  moment in terms of localized NLMO and NBO
contributions, including all terms  whose  contribution  (in
vector norm) exceeds the `dval' threshold.

  Example:#T     DIPOLE=0.1

#NThis example would print out dipole contributions  of  all
NBOs (and their delocalization interactions) of magnitude ge
0.1hsp D.


#NBoth the BEND and E2PERT keywords are activated by default
at  the  standard PRINT level option (see Section B.2.6); to
get an example of dipole moment analysis, include the  keyl-
ist
 #T
     $NBO  DIPOLE  $END

#Nin your input file.  Note that the DIPOLE keyword leads to
an  analysis  in  terms  of both NBOs and NLMOs, so that the
NLMO keyword (Section B.2.2) is automatically  activated  in
this case.  #IB.2.4 Matrix Output Keywords#N

0 The keywords in this group activate the printing of  vari-
ous  matrices  to  the  output file, or their writing to (or
reading from) external disk files.  The large number of key-
words  in  this  group provide great flexibility in printing
out the details of the successive transformations,

eps1  eps2

or the matrices of various operators in the  natural  local-
ized  basis  sets.  This ordered sequence of transformations
forms the basis for naming the keywords.


#_Keyword Names#/

0 The keyword for printing the matrix for a particular basis
transformation,   IN7  arr   OUT,  is  constructed  from  the
corresponding acronymns for the two sets in the generic form
``INOUT''.   For  example, the transformation AO7 arr  NBO is
keyed as  ``AONBO'',  while  that  from  NBOs  to  NLMOs  is
correspondingly ``NBONLMO''.  The transformations are always
specified  in  the  ordered  sequence  shown  above   (i.e.,
``AONBO''  is  allowed,  but  ``NBOAO''  is  an unrecognized
`backward' keyword).   Keywords  are  recognized  for  #Iall
possible#N  transformations from the input AOs to other sets



                       July 11, 1995





                           - 32 -


(NAO,
NHO, NBO, NLMO, MO, or the pre-orthogonal PNAO, PNHO,  PNBO,
PNLMO  sets)  in  the  overall sequence leading to canonical
MOs, i.e.,

AONAO  AONHO  AONBO  AONLMO   AOMO  AOPNAO   AOPNHO   AOPNBO
AOPNLMO

and from each of the orthonormal natural localized  sets  to
sets lying to the right in the sequence, i.e.,

NAONHO  NAONBO  NAONLMO  NAOMO

NHONBO  NHONLMO  NHOMO

NBONLMO  NBOMO

NLMOMO

The matrix T#dIN,OUT#u for a specified IN7 arr  OUT transform
has  rows labelled by the IN set and columns labelled by the
OUT set.

0 One can also print out the matrix representations  of  the
Fock  matrix  (F),  density  matrix  (DM),  or dipole moment
matrix (DI) in the input AO set or any of the natural local-
ized  sets (NAO, NHO, NBO, or NLMO).  The corresponding key-
word is constructed by combining the  abbreviation  (M)  for
the operator with that for the set (SET) in the generic form
``MSET''.  For example, to print the Fock matrix (F) in  the
NBO  set,  use  the keyword ``FNBO'', or to print the dipole
matrix in the NLMO basis, use ``DINLMO''.  (For  the  dipole
matrix   keywords,  all  three  vector  components  will  be
printed.)  One can also print out elements  of  the  overlap
matrix  (S)  in  the  input  AO  basis  or  any of the `pre-
orthogonal' sets (PNAO, PNHO, PNBO, or PNLMO), using,  e.g.,
``SPNAO''  for  the  overlap  matrix in the PNAO basis.  The
complete set of allowed keywords for operator matrices is:

FAO  FNAO  FNHO  FNBO  FNLMO

DMAO  DMNAO  DMNHO  DMNBO  DMNLMO

DIAO  DINAO  DINHO  DINBO  DINLMO

SAO  SPNAO  SPNHO  SPNBO  SPNLMO

Other desired transformations can be readily  obtained  from
the keyword transformations by matrix multiplication.


#_Keyword Parameters#/

0 Each generic matrix keyword  (``MATKEY'')  can  include  a



                       July 11, 1995





                           - 33 -


parameter
that specifies the output operation to be performed  on  the
matrix.   The  allowed  MATKEY  parameters  are of two types
(three for AONAO, NAONBO; see below):

(print out the matrix  in  the  standard  output  file,  'c'
columns)

(write out the matrix to disk file #In#N)

#NThe first (P[c]) parameter is used to  control  output  to
the  standard  output  file.   When  the  MATKEY  keyword is
inserted in the $NBO keylist with no parameters, the  matrix
is by default printed (in its entirety) in the standard out-
put file.  Thus, ``MATKEY=P'' would be equivalent to  ``MAT-
KEY'',  with no parameters.  The complete `P[c]' form of the
print parameter serves to truncate the printed matrix output
to a specified number of columns [c].  For example, to print
out only the first 16 columns of a matrix, use the form
 #T
     MATKEY=P16         (print 16 columns)

#NFor certain matrices, one can also  restrict  printing  to
only  the valence (VAL) or Lewis (LEW) columns with modified
`[c]' specifiers.  For the transformations to MOs,  use  the
form
 #T
     MATKEY=PVAL        (print core  +  valence  MO  columns
only)

#Nwhere ``MATKEY'' is AOMO, NAOMO, NHOMO, NBOMO,  or  NLMOMO
(only).   This  will print out only the occupied MOs and the
lowest few unoccupied MOs, e.g., the six lowest virtual  MOs
of  the methylamine example (Section A.3), though not neces-
sarily those with pre#|dominant  valence  character.   Simi-
larly,  for  the  transformations  to NBOs or NLMOs, use the
form
 #T
     MATKEY=PLEW        (print Lewis orbital columns only)

#Nwhere  ``MATKEY''  is  AONBO,  NHONBO,   NAONBO,   AONLMO,
NAONLMO,  NHONLMO,  NBONLMO  (or  AOMO, NAOMO, NHOMO, NBOMO,
NLMOMO).  This prints out the Lewis  NBOs  or  occupied  MOs
only, e.g., only the nine occupied NBOs or MOs of the methy-
lamine example.  Judicious use  of  these  print  parameters
keeps  printed  output  within reasonable bounds in calcula-
tions with large basis sets.

#NThe second type of MATKEY  parameter  (W[n])  is  used  to
write  the matrix (in its entirety) to a specified disk file
[n].  By default,  each  keyword  transformation  matrix  is
associated  with  a  particular logical file number (LFN) in
the range 31-49, as shown in the table below:




                       July 11, 1995





                           - 34 -


#NWhen the ``MATKEY=Wn'' keyword is  inserted  in  the  $NBO
keylist  with  no  `n'  specifier,  the matrix is by default
written  out  (in  its  entirety)  to   this   LFN.    Thus,
``MATKEY=W''  is equivalent to ``MATKEY=Wn'' if ``n'' is the
default LFN for that keyword.  Use the ``Wn''  parameter  to
direct  output  to any non-default LFN disk file.  For exam-
ple, the keyword
 #T
     AONBO=W22

#Nwould write out the AO7 arr  NBO transformation to LFN = 22
(rather than the default LFN = 37).

0 The format of the  printed  output  under  the  print  `P'
parameter  differs  from  that  written  to an external file
under the `W' parameter.  The `P'  output  (intended  for  a
human  reader)  includes  an identifying label for each row,
and gives the numerical entries to somewhat lesser precision
(F8.4  format) than the corresponding `W' output (F15.9 for-
mat), which is usually intended as input to another program.
Use  the ``MATKEY=W6'' keyword to route the more precise `W'
form of the matrix to the standard output file, LFN 6.

0 For the  AONAO,  NAONBO  matrices  (only),  one  can  also
include a read parameter (R),
 #T
     AONAO=Rn
     NAONBO=Rn

#Nwhich causes the matrix to be input to  the  program  from
LFN  #In#N.   This  parameter  has  the effect of `freezing'
orbitals to a set prescribed in the input file (thus bypass-
ing the NBO optimization of these orbitals for the molecular
system).  For example, the keyword ``NAONBO=R44'' would have
the effect of freezing the NAO7 arr  NBO transformation coef-
ficients to the form specified in LFN  44  (perhaps  written
with the ``NAONBO=W44'' keyword in a previous calculation on
isolated molecules, and now to be used in a calculation on a
molecular  complex).   Similarly,  the keyword ``AONAO=R45''
could be used to force the analysis of an excited  state  to
be  carried  out  in  terms  of the NAOs of the ground state
(previously written out  with  the  ``AONAO=W45''  keyword).
#IB.2.5 Other Output Control Keywords#N

0 The keywords in this group also help to  control  the  I/O
produced by a specified set of job options, and thus supple-
ment the keywords of the  previous  section.   However,  the
keywords  of  this  section  `steer' the flow of information
that is routinely produced by the NBO  program  (or  can  be
passed  through  from  the  ESS  program) without materially
affecting the actual jobs performed by the NBO program.  The
options associated with each keyword are tabulated below:

#IOPTION DESCRIPTION#N



                       July 11, 1995





                           - 35 -


Set the logical file number (LFN) for  NBO  program  output.
The  default LFN is #In#N = 6, the usual LFN for output from
the ESS program.  This option can be used to steer  the  NBO
section of the job output to a desired file.

  Example:#T  LFNPR=25   (re-direct NBO output to LFN 25)
 #N Request additional details  of  the  NBO  search.   This
option  (primarily  for  programming and debugging purposes)
records details of the NBO loops over atoms and atom  pairs,
enroute to the final NBOs.

Request print-out of the NAO-Wiberg  Bond  Index  array  and
related  valency  indices  (Section B.6.5).  The elements of
this array are the sums of squares of  off-diagonal  density
matrix elements between pairs of atoms in the NAO basis, and
are the NAO counterpart of the Wiberg bond index [K. Wiberg,
Tetrahedron  #B24#N, 1083-1096 (1968)].  (This bond index is
routinely used to `screen' atom pairs for  possible  bonding
in the NBO search, but the values are not printed unless the
BNDIDX keyword is activated.)

Request writing of information concerning the AO  basis  set
(geometrical positions, orbital exponents, contraction coef-
ficients, etc.) to an external file, LFN 31.  This is a por-
tion of the information needed by the ORB#|PLOT orbital con-
tour plotting programs (cf. ``PLOT'' keyword below.)


_1.  _R_e_q_u_e_s_t _w_r_i_t_i_n_g _o_f #_I_a_l_l#_N  _f_i_l_e_s  _r_e_q_u_i_r_e_d  _b_y  _o_r_b_i_t_a_l
_c_o_n_t_o_u_r  _p_l_o_t_t_i_n_g  _p_r_o_g_r_a_m_s  _O_R_B#|_P_L_O_T.   _T_h_i_s _a_c_t_i_v_a_t_e_s _t_h_e
_A_O_I_N_F_O _k_e_y_w_o_r_d, _a_s _w_e_l_l _a_s _a_l_l _t_h_e _n_e_c_e_s_s_a_r_y  _m_a_t_r_i_x  _o_u_t_p_u_t
_k_e_y_w_o_r_d_s  (_A_O_N_B_O=_W_3_7,  _e_t_c.)  _t_h_a_t  _c_o_u_l_d  _b_e  _r_e_q_u_i_r_e_d  _f_o_r
_O_R_B_P_L_O_T.

_R_e_q_u_e_s_t _w_r_i_t_i_n_g _t_h_e _F_I_L_E_4_7 `_a_r_c_h_i_v_e' _f_i_l_e _t_o  _e_x_t_e_r_n_a_l  _d_i_s_k
_f_i_l_e  _L_F_N  =  #_I_n#_N  (_o_r,  _i_f  ``=_n'' _i_s _n_o_t _p_r_e_s_e_n_t, _t_o _t_h_e
_d_e_f_a_u_l_t _L_F_N = _4_7).  _T_h_i_s _f_i_l_e _c_a_n _s_e_r_v_e _a_s _t_h_e _i_n_p_u_t _f_i_l_e _t_o
_r_u_n  _t_h_e  _G_E_N_N_B_O  _p_r_o_g_r_a_m _i_n _s_t_a_n_d-_a_l_o_n_e _m_o_d_e, _t_o _r_e_p_e_a_t _t_h_e
_N_B_O _a_n_a_l_y_s_i_s (_p_o_s_s_i_b_l_y _w_i_t_h _n_e_w _j_o_b _o_p_t_i_o_n_s) _w_i_t_h_o_u_t _r_e_p_e_a_t_-
_i_n_g _t_h_e _c_a_l_c_u_l_a_t_i_o_n _o_f _t_h_e _w_a_v_e_f_u_n_c_t_i_o_n (_S_e_c_t_i_o_n _B._7).

_R_e_q_u_e_s_t _w_r_i_t_i_n_g _t_h_e _N_B_O _d_i_r_e_c_t _a_c_c_e_s_s _f_i_l_e (_D_A_F) _t_o _e_x_t_e_r_n_a_l
_d_i_s_k  _f_i_l_e _L_F_N = #_I_n#_N (_o_r, _i_f ``=_n'' _i_s _n_o_t _p_r_e_s_e_n_t, _t_o _t_h_e
_d_e_f_a_u_l_t _L_F_N =_4_8).  #_I_B._2._6 _P_r_i_n_t _L_e_v_e_l _K_e_y_w_o_r_d_s#_N

_0 _T_h_e _k_e_y_w_o_r_d ``_P_R_I_N_T=_n'' (#_I_n#_N = _0-_4) _c_a_n _b_e _u_s_e_d _t_o  _g_i_v_e
_c_o_n_v_e_n_i_e_n_t, _f_l_e_x_i_b_l_e _c_o_n_t_r_o_l _o_f _a_l_l _N_B_O _o_u_t_p_u_t _i_n _t_e_r_m_s _o_f _a
_s_p_e_c_i_f_i_e_d _p_r_i_n_t _l_e_v_e_l #_I_n#_N.  _T_h_i_s _k_e_y_w_o_r_d _a_c_t_i_v_a_t_e_s  _g_r_o_u_p_s
_o_f _k_e_y_w_o_r_d_s _i_n _a _h_e_i_r_a_r_c_h_i_c_a_l _m_a_n_n_e_r, _a_n_d _t_h_u_s _i_n_c_r_e_m_e_n_t_a_l_l_y
_i_n_c_r_e_a_s_e_s _t_h_e _v_o_l_u_m_e _o_f _o_u_t_p_u_t, _r_a_n_g_i_n_g _f_r_o_m #_I_n_o#_N _N_B_O _o_u_t_-
_p_u_t  (_P_R_I_N_T=_0) _t_o _a _c_o_n_s_i_d_e_r_a_b_l_e _v_o_l_u_m_e _o_f _d_e_t_a_i_l (_P_R_I_N_T=_4).
_T_h_e _k_e_y_w_o_r_d_s _a_s_s_o_c_i_a_t_e_d _w_i_t_h _e_a_c_h _p_r_i_n_t _l_e_v_e_l _a_r_e  _t_a_b_u_l_a_t_e_d
_b_e_l_o_w [_d_e_f_a_u_l_t _v_a_l_u_e, _P_R_I_N_T=_2]:




                       July 11, 1995





                           - 36 -


_F_o_r _e_a_c_h _p_r_i_n_t _l_e_v_e_l #_I_n#_N,  _t_h_e  _N_B_O  _o_u_t_p_u_t  _w_i_l_l  _i_n_c_l_u_d_e
_i_t_e_m_s _a_c_t_i_v_a_t_e_d _b_y _t_h_e _l_i_s_t_e_d _k_e_y_w_o_r_d_s, _a_s _w_e_l_l _a_s _a_l_l _i_t_e_m_s
_f_r_o_m _l_o_w_e_r _p_r_i_n_t _l_e_v_e_l_s.

_0 _W_h_e_n _a_d_d_i_t_i_o_n_a_l _k_e_y_w_o_r_d_s _a_r_e _i_n_c_l_u_d_e_d _w_i_t_h  _a  ``_P_R_I_N_T=_n''
_k_e_y_w_o_r_d  _i_n  _t_h_e  $_N_B_O  _k_e_y_l_i_s_t, _t_h_e _N_B_O _o_u_t_p_u_t _i_n_c_l_u_d_e_s _t_h_e
_a_d_d_i_t_i_o_n_a_l _k_e_y_w_o_r_d _i_t_e_m_s _a_s _w_e_l_l _a_s  _t_h_o_s_e  _i_m_p_l_i_e_d  _b_y  _t_h_e
_p_r_i_n_t  _l_e_v_e_l.   _T_h_i_s _c_a_n _b_e _u_s_e_d _t_o _t_a_i_l_o_r _t_h_e _N_B_O _o_u_t_p_u_t _t_o
_v_i_r_t_u_a_l_l_y _a_n_y _s_e_l_e_c_t_i_o_n _o_f _o_u_t_p_u_t _i_t_e_m_s.  _F_o_r  _e_x_a_m_p_l_e,  _t_h_e
_k_e_y_l_i_s_t
 #_T
     $_N_B_O  _P_R_I_N_T=_2  _N_L_M_O  _F_N_B_O=_P  _N_A_O_M_O=_P_1_1  $_E_N_D

#_N_w_o_u_l_d _a_d_d _t_o _t_h_e _s_t_a_n_d_a_r_d _m_e_t_h_y_l_a_m_i_n_e _o_u_t_p_u_t _f_i_l_e _o_f  _S_e_c_-
_t_i_o_n  _A._3  _a_n _N_L_M_O _s_u_m_m_a_r_y _t_a_b_l_e, _t_h_e _F_o_c_k _m_a_t_r_i_x _i_n _t_h_e _N_B_O
_b_a_s_i_s, _a_n_d _t_h_e _t_r_a_n_s_f_o_r_m_a_t_i_o_n _c_o_e_f_f_i_c_i_e_n_t_s _f_o_r _t_h_e _f_i_r_s_t  _1_1
_m_o_l_e_c_u_l_a_r  _o_r_b_i_t_a_l_s _i_n _t_e_r_m_s _o_f _N_A_O_s.  _S_i_m_i_l_a_r_l_y, _t_o _p_r_o_d_u_c_e
_t_h_e _N_P_A _l_i_s_t_i_n_g _o_n_l_y, _o_n_e _c_o_u_l_d _u_s_e
 #_T
     $_N_B_O  _P_R_I_N_T=_1  _S_K_I_P_B_O  $_E_N_D

#_N_o_r
 #_T
     $_N_B_O  _P_R_I_N_T=_0  _N_P_A  $_E_N_D

#_N[_T_h_e_r_e _i_s _a_c_t_u_a_l_l_y _a _s_l_i_g_h_t  _d_i_f_f_e_r_e_n_c_e  _b_e_t_w_e_e_n  _t_h_e  _t_w_o
_e_x_a_m_p_l_e_s:  _T_h_e _N_B_O_s _a_r_e _d_e_t_e_r_m_i_n_e_d _b_y _d_e_f_a_u_l_t (_o_n_c_e _t_h_e $_N_B_O
_k_e_y_l_i_s_t _i_s _e_n_c_o_u_n_t_e_r_e_d), _e_v_e_n _i_f _a_l_l  _o_u_t_p_u_t  _i_s  _s_u_p_p_r_e_s_s_e_d
_w_i_t_h  _P_R_I_N_T=_0;  _i_n  _t_h_e  _f_i_r_s_t  _e_x_a_m_p_l_e,  _t_h_e _k_e_y_w_o_r_d _S_K_I_P_B_O
_b_y_p_a_s_s_e_s _N_B_O _d_e_t_e_r_m_i_n_a_t_i_o_n, _w_h_e_r_e_a_s _i_n  _t_h_e  _s_e_c_o_n_d  _e_x_a_m_p_l_e
_t_h_e  _N_B_O_s  _a_r_e  _s_t_i_l_l  _d_e_t_e_r_m_i_n_e_d  `_i_n _b_a_c_k_g_r_o_u_n_d.'] #_I_B._2._7
_S_e_m_i-_D_o_c_u_m_e_n_t_e_d _A_d_d_i_t_i_o_n_a_l _K_e_y_w_o_r_d_s#_N

_0 _S_o_m_e _a_d_d_i_t_i_o_n_a_l _k_e_y_w_o_r_d_s _a_r_e _l_i_s_t_e_d _b_e_l_o_w _t_h_a_t _m_a_y _o_f  _u_s_e
_t_o _s_p_e_c_i_a_l_i_s_t_s _o_r _p_r_o_g_r_a_m _d_e_v_e_l_o_p_e_r_s:

#_I_O_P_T_I_O_N _D_E_S_C_R_I_P_T_I_O_N#_N

_S_e_t _t_h_e _t_h_r_e_s_h_o_l_d _o_f  _o_r_b_i_t_a_l  _o_c_c_u_p_a_n_c_y  _d_e_s_i_r_e_d  _f_o_r  _b_o_n_d
_o_r_b_i_t_a_l  _s_e_l_e_c_t_i_o_n.   _I_f  _t_h_i_s  _i_s _n_o_t _i_n_c_l_u_d_e_d, _t_h_e _d_e_f_a_u_l_t
_o_c_c_u_p_a_n_c_y [_1._9_0] _w_i_l_l _b_e _u_s_e_d  (_o_r  _v_a_l_u_e_s  _d_e_c_r_e_a_s_i_n_g  _f_r_o_m
_1._9_0  _t_o  _1._5_0  _b_y  _0._1_0  _s_t_e_p_s, _i_f _t_h_e _R_E_S_O_N_A_N_C_E _k_e_y_w_o_r_d _i_s
_i_n_c_l_u_d_e_d).

_S_e_t _t_h_e _p_r_o_j_e_c_t_i_o_n _t_h_r_e_s_h_o_l_d [_d_e_f_a_u_l_t _0._2_0] _t_o _d_e_t_e_r_m_i_n_e  _i_f
_a  `_n_e_w'  _h_y_b_r_i_d  _o_r_b_i_t_a_l  _h_a_s _t_o_o _h_i_g_h _o_v_e_r_l_a_p _w_i_t_h _h_y_b_r_i_d_s
_p_r_e_v_i_o_u_s_l_y _f_o_u_n_d.

_P_r_i_n_t _t_o_t_a_l _g_r_o_s_s _M_u_l_l_i_k_e_n _p_o_p_u_l_a_t_i_o_n_s _b_y _a_t_o_m.

_P_r_i_n_t _g_r_o_s_s _M_u_l_l_i_k_e_n _p_o_p_u_l_a_t_i_o_n_s, _b_y _o_r_b_i_t_a_l _a_n_d _a_t_o_m.

_R_e_v_i_s_e_s  _P_A_O  _t_o  _P_N_A_O  _t_r_a_n_s_f_o_r_m_a_t_i_o_n   _m_a_t_r_i_x   _b_y   _p_o_s_t-
_m_u_l_t_i_p_l_y_i_n_g  _b_y  #_B_T#_N#_d_R_y_d#_u  _a_n_d #_B_T#_N#_d_r_e_d#_u [_s_e_e _t_h_e _N_P_A



                       July 11, 1995





                           - 37 -


_p_a_p_e_r:
_A. _E. _R_e_e_d, _R. _B. _W_e_i_n_s_t_o_c_k, _a_n_d _F. _W_e_i_n_h_o_l_d, _J. _C_h_e_m. _P_h_y_s.
#_B_8_3#_N, _7_3_5-_7_4_6 (_1_9_8_5)].

_I_n_p_u_t _o_r _o_u_t_p_u_t _o_f _p_u_r_e _A_O (_P_A_O) _t_o _p_r_e-_N_A_O (_P_N_A_O) _t_r_a_n_s_f_o_r_-
_m_a_t_i_o_n.   _T_h_e _P_A_O_s _a_r_e _A_O_s _o_f _p_u_r_e _a_n_g_u_l_a_r _m_o_m_e_n_t_u_m _s_y_m_m_e_t_r_y
(_r_a_t_h_e_r _t_h_a_n _c_a_r_t_e_s_i_a_n _g_a_u_s_s_i_a_n_s).  _T_h_i_s _k_e_y_w_o_r_d _c_a_n _b_e _u_s_e_d
_w_i_t_h  _r_e_a_d (`_R'), _w_r_i_t_e (`_W', _d_e_f_a_u_l_t _L_F_N _4_3) _o_r _p_r_i_n_t (`_P')
_p_a_r_a_m_e_t_e_r_s.

_P_r_i_n_t _o_u_t _t_h_e _b_o_n_d-_o_r_d_e_r _m_a_t_r_i_x (_F_o_c_k-_D_i_r_a_c _d_e_n_s_i_t_y  _m_a_t_r_i_x)
_i_n  _t_h_e  _b_a_s_i_s  _s_e_t  _o_f _i_n_p_u_t _A_O_s.  _T_h_i_s _k_e_y_w_o_r_d _c_a_n _b_e _u_s_e_d
_w_i_t_h _w_r_i_t_e (`_W', _d_e_f_a_u_l_t _L_F_N _4_9) _o_r _p_r_i_n_t (`_P') _p_a_r_a_m_e_t_e_r_s.


#_B_B._3 _T_H_E $_C_O_R_E _L_I_S_T#_N

_0 _I_n _t_h_e _L_e_w_i_s _s_t_r_u_c_t_u_r_e _p_i_c_t_u_r_e, _t_h_e _i_n_n_e_r `_c_o_r_e'  _e_l_e_c_t_r_o_n
_p_a_i_r_s  _a_r_e _p_i_c_t_u_r_e_d _a_s _o_c_c_u_p_y_i_n_g _o_r_b_i_t_a_l_s _h_a_v_i_n_g _e_s_s_e_n_t_i_a_l_l_y
_i_s_o_l_a_t_e_d _a_t_o_m_i_c _o_r_b_i_t_a_l _c_h_a_r_a_c_t_e_r.  _I_n _N_B_O  _p_a_r_l_a_n_c_e,  _t_h_e_s_e
_c_o_r_e  _o_r_b_i_t_a_l_s  _c_o_r_r_e_s_p_o_n_d  _t_o _1-_c_e_n_t_e_r _u_n_h_y_b_r_i_d_i_z_e_d _N_A_O_s _o_f
_n_e_a_r-_m_a_x_i_m_u_m _o_c_c_u_p_a_n_c_y, _w_h_i_c_h _a_r_e _i_s_o_l_a_t_e_d  _o_n  _e_a_c_h  _c_e_n_t_e_r
_b_e_f_o_r_e  _t_h_e  _m_a_i_n  _N_B_O  _s_e_a_r_c_h  _b_e_g_i_n_s _f_o_r _l_o_c_a_l_i_z_e_d _v_a_l_e_n_c_e
_e_l_e_c_t_r_o_n _p_a_i_r_s.  _A _w_a_r_n_i_n_g _m_e_s_s_a_g_e _i_s _p_r_i_n_t_e_d _i_f  _t_h_e  _o_c_c_u_-
_p_a_n_c_y _o_f _a _p_r_e_s_u_m_e_d _c_l_o_s_e_d-_s_h_e_l_l _c_o_r_e _N_B_O _f_a_l_l_s _b_e_l_o_w _1._9_9_9_0
_e_l_e_c_t_r_o_n_s (_o_r _0._9_9_9_0 _i_n _t_h_e _o_p_e_n-_s_h_e_l_l _c_a_s_e), _i_n_d_i_c_a_t_i_v_e  _o_f
_a  _p_o_s_s_i_b_l_e  _c_o_r_e-_v_a_l_e_n_c_e _m_i_x_i_n_g _e_f_f_e_c_t _o_f _p_h_y_s_i_c_a_l _s_i_g_n_i_f_i_-
_c_a_n_c_e.

_0 [_I_n _p_r_e_v_i_o_u_s _v_e_r_s_i_o_n_s _o_f _t_h_e _N_B_O  _p_r_o_g_r_a_m,  _c_o_r_e  _o_r_b_i_t_a_l_s
_h_a_v_i_n_g  _t_h_e  _e_x_p_e_c_t_e_d  _p_u_r_e  _a_t_o_m_i_c  _c_h_a_r_a_c_t_e_r  _a_r_e _f_o_u_n_d _i_n
_e_s_s_e_n_t_i_a_l_l_y _a_l_l _c_a_s_e_s, _e_x_c_e_p_t _w_h_e_r_e _a_n  `_a_c_c_i_d_e_n_t_a_l'  _d_e_g_e_n_-
_e_r_a_c_y  _i_n  _o_c_c_u_p_a_n_c_y _o_f _c_o_r_e _a_n_d _v_a_l_e_n_c_e _l_o_n_e _p_a_i_r_s _l_e_a_d_s _t_o
_u_n_d_e_s_i_r_a_b_l_e _c_o_r_e-_v_a_l_e_n_c_e _m_i_x_i_n_g; _t_h_e _p_r_e_s_e_n_t _v_e_r_s_i_o_n  _e_x_p_l_i_-
_c_i_t_l_y  _i_s_o_l_a_t_e_s _c_o_r_e _p_a_i_r_s _a_s _u_n_h_y_b_r_i_d_i_z_e_d _N_A_O_s _p_r_i_o_r _t_o _t_h_e
_m_a_i_n _N_B_O _s_e_a_r_c_h _t_o _p_r_e_v_e_n_t _t_h_i_s _u_n_p_h_y_s_i_c_a_l _e_f_f_e_c_t.]

_0 _T_h_e _N_B_O _p_r_o_g_r_a_m _c_o_n_t_a_i_n_s _a _t_a_b_l_e _g_i_v_i_n_g _t_h_e _n_o_m_i_n_a_l _n_u_m_b_e_r
_o_f  _c_o_r_e _o_r_b_i_t_a_l_s _t_o _b_e _i_s_o_l_a_t_e_d _o_n _e_a_c_h _t_y_p_e _o_f _a_t_o_m (_e._g.,
_1#_I_s#_N _f_o_r _f_i_r_s_t-_r_o_w _a_t_o_m_s _L_i-_N_e, _1#_I_s#_N, _2#_I_s#_N, _2#_I_p#_N _f_o_r
_s_e_c_o_n_d-_r_o_w  _a_t_o_m_s  _N_a-_A_r,  _e_t_c.).   _A_t _t_i_m_e_s, _h_o_w_e_v_e_r, _i_t _i_s
_i_n_t_e_r_e_s_t_i_n_g _t_o _e_x_a_m_i_n_e _t_h_e _e_f_f_e_c_t _o_f _a_l_l_o_w_i_n_g _c_o_r_e  _o_r_b_i_t_a_l_s
_t_o  _m_i_x _i_n_t_o _t_h_e _b_o_n_d_i_n_g _h_y_b_r_i_d_s, _o_r _t_o _h_y_b_r_i_d_i_z_e (_p_o_l_a_r_i_z_e)
_a_m_o_n_g _t_h_e_m_s_e_l_v_e_s.  _T_h_i_s _c_a_n _b_e _a_c_c_o_m_p_l_i_s_h_e_d _b_y  _i_n_c_l_u_d_i_n_g  _a
$_C_O_R_E  _k_e_y_l_i_s_t  _t_o _s_p_e_c_i_f_y _t_h_e _n_u_m_b_e_r _o_f _c_o_r_e _o_r_b_i_t_a_l_s _t_o _b_e
_i_s_o_l_a_t_e_d _o_n _e_a_c_h _a_t_o_m_i_c _c_e_n_t_e_r, _t_h_u_s _m_o_d_i_f_y_i_n_g  _t_h_e  _n_o_m_i_n_a_l
_c_o_r_e  _t_a_b_l_e.   _U_n_l_i_k_e  _o_t_h_e_r  _N_B_O  _k_e_y_l_i_s_t_s,  _t_h_e $_C_O_R_E _l_i_s_t
_i_n_c_l_u_d_e_s _o_n_l_y _i_n_t_e_g_e_r_s (_r_a_t_h_e_r _t_h_a_n _k_e_y_w_o_r_d_s) _t_o _s_p_e_c_i_f_y _t_h_e
_c_o_r_e  _m_o_d_i_f_i_c_a_t_i_o_n_s,  _b_u_t _t_h_e _r_u_l_e_s _a_r_e _o_t_h_e_r_w_i_s_e _s_i_m_i_l_a_r _t_o
_t_h_o_s_e _f_o_r _o_t_h_e_r _k_e_y_l_i_s_t_s.  _T_h_e $_C_O_R_E _l_i_s_t (_i_f _i_n_c_l_u_d_e_d) _m_u_s_t
_f_o_l_l_o_w  _t_h_e  $_N_B_O  _k_e_y_l_i_s_t  _a_n_d  _p_r_e_c_e_d_e _t_h_e $_C_H_O_O_S_E _o_r $_D_E_L
_k_e_y_l_i_s_t_s.

_0 _T_h_e _f_o_r_m_a_t _o_f _t_h_e $_C_O_R_E _m_o_d_i_f_i_c_a_t_i_o_n _l_i_s_t _i_s:



                       July 11, 1995





                           - 38 -


_T_h_e _k_e_y_w_o_r_d ``$_C_O_R_E''

_P_a_i_r_s _o_f _i_n_t_e_g_e_r_s, _o_n_e _p_a_i_r  _f_o_r  _e_a_c_h  _c_e_n_t_e_r.   _T_h_e  _f_i_r_s_t
_i_n_t_e_g_e_r _i_n_d_i_c_a_t_e_s _t_h_e _a_t_o_m_i_c _c_e_n_t_e_r (_i_n _t_h_e _n_u_m_b_e_r_i_n_g _o_f _t_h_e
_m_a_i_n _E_S_S) _a_n_d _t_h_e _s_e_c_o_n_d _i_s _t_h_e _n_u_m_b_e_r _o_f _c_o_r_e  _o_r_b_i_t_a_l_s  _t_o
_b_e  _i_s_o_l_a_t_e_d  _o_n  _t_h_a_t  _a_t_o_m.   _N_o_t_e _t_h_a_t _a_t_o_m_i_c _c_e_n_t_e_r_s _n_o_t
_i_n_c_l_u_d_e_d _i_n _t_h_e _C_O_R_E _l_i_s_t _a_r_e _a_s_s_i_g_n_e_d _d_e_f_a_u_l_t _c_o_r_e_s.

_T_h_e _k_e_y_w_o_r_d ``$_E_N_D'', _t_o _i_n_d_i_c_a_t_e _t_h_e _e_n_d _o_f _c_o_r_e _i_n_p_u_t.

_T_h_e _e_n_t_i_r_e _l_i_s_t _m_a_y _a_l_s_o _b_e _c_o_n_d_e_n_s_e_d _t_o _a _s_i_n_g_l_e _l_i_n_e,  _b_u_t
_t_h_e  _w_o_r_d ``$_C_O_R_E'' _m_u_s_t _o_c_c_u_r _a_s _t_h_e _f_i_r_s_t _w_o_r_d _o_f _t_h_e _l_i_n_e
_a_n_d ``$_E_N_D'' _a_s _t_h_e _l_a_s_t _w_o_r_d; _t_h_a_t _i_s, _t_h_e  _c_o_r_e  _m_o_d_i_f_i_c_a_-
_t_i_o_n  _k_e_y_l_i_s_t  _c_a_n_n_o_t _c_o_n_t_i_n_u_e _o_n _a _l_i_n_e _t_h_a_t _c_o_n_t_a_i_n_s _o_t_h_e_r
_k_e_y_l_i_s_t _i_n_f_o_r_m_a_t_i_o_n.

_0 _T_h_e _c_o_r_e _o_r_b_i_t_a_l_s _a_r_e  _i_s_o_l_a_t_e_d  _b_y  _o_c_c_u_p_a_n_c_y,  _t_h_e  _m_o_s_t
_o_c_c_u_p_i_e_d  _N_A_O_s  _b_e_i_n_g _f_i_r_s_t _s_e_l_e_c_t_e_d, _a_n_d _f_u_l_l _s_u_b_s_h_e_l_l_s _a_r_e
_i_s_o_l_a_t_e_d _a_t _a _t_i_m_e.  _T_h_u_s, _f_o_r _e_x_a_m_p_l_e, _t_o _s_e_l_e_c_t  _t_h_e  _f_i_v_e
_o_r_b_i_t_a_l_s _o_f _t_h_e #_I_n#_N = _1 _a_n_d #_I_n#_N = _2 _s_h_e_l_l_s _a_s _c_o_r_e _o_r_b_i_-
_t_a_l_s, _i_t _w_o_u_l_d _m_a_k_e _n_o _d_i_f_f_e_r_e_n_c_e _t_o _s_e_l_e_c_t ``_3''  _o_r  ``_4''
(_i_n_s_t_e_a_d  _o_f  ``_5''), _s_i_n_c_e _a_l_l _t_h_r_e_e _o_f _t_h_e_s_e _c_h_o_i_c_e_s _w_o_u_l_d
_s_p_e_c_i_f_y _a _c_o_r_e _c_o_n_t_a_i_n_i_n_g _a _1#_I_s#_N, _2#_I_s#_N,  _a_n_d  _a_l_l  _t_h_r_e_e
_2#_I_p#_N  _o_r_b_i_t_a_l_s.   _T_h_e $_C_O_R_E _m_o_d_i_f_i_c_a_t_i_o_n _l_i_s_t _i_s _r_e_a_d _o_n_l_y
_o_n_c_e, _a_n_d _a_p_p_l_i_e_s _t_o _b_o_t_h _l_p_h_a  _a_n_d7777777777777 t99a999999  s99p99i99n9999 m99a99n99i99f99o99l99d99s9999 i99n9999 a99n9999 o99_p7777777777777_n-_s_h_e_l_l  _c_a_l_c_u_l_a_-
_t_i_o_n.

_A_n _e_x_a_m_p_l_e, _a_p_p_r_o_p_r_i_a_t_e _f_o_r _N_i(_1)-_C(_2)-_O(_3) _w_i_t_h  _t_h_e  _i_n_d_i_-
_c_a_t_e_d _n_u_m_b_e_r_i_n_g _o_f _a_t_o_m_s, _i_s _s_h_o_w_n _b_e_l_o_w:
 #_T
     $_C_O_R_E
       _1   _5
     $_E_N_D

#_N_T_h_i_s _w_o_u_l_d _d_i_r_e_c_t _t_h_e _N_B_O _p_r_o_g_r_a_m _t_o _i_s_o_l_a_t_e _o_n_l_y  _5  _c_o_r_e
_o_r_b_i_t_a_l_s  _o_n _N_i_c_k_e_l (_a_t_o_m _1), _r_a_t_h_e_r _t_h_a_n _t_h_e _n_o_m_i_n_a_l _9 _c_o_r_e
_o_r_b_i_t_a_l_s.  _I_n _o_t_h_e_r _w_o_r_d_s, _o_n_l_y _1#_I_s#_N, _2#_I_s#_N,  _a_n_d  _2#_I_p#_N
_o_r_b_i_t_a_l_s  _w_i_l_l  _b_e _c_o_n_s_i_d_e_r_e_d _a_s _c_o_r_e _o_r_b_i_t_a_l_s _i_n _t_h_e _s_e_a_r_c_h
_f_o_r _N_B_O_s _o_f _N_i_C_O, _a_l_l_o_w_i_n_g _t_h_e _3#_I_s#_N _a_n_d _3#_I_p#_N _o_r_b_i_t_a_l_s _t_o
_m_i_x  _w_i_t_h  _v_a_l_e_n_c_e _N_A_O_s _i_n _b_o_n_d _f_o_r_m_a_t_i_o_n.  _S_i_n_c_e _t_h_e _c_a_r_b_o_n
_a_n_d _o_x_y_g_e_n _a_t_o_m_s _w_e_r_e _n_o_t _i_n_c_l_u_d_e_d _i_n _t_h_e _m_o_d_i_f_i_c_a_t_i_o_n _l_i_s_t,
_t_h_e  _n_o_m_i_n_a_l  _s_e_t _o_f _c_o_r_e _o_r_b_i_t_a_l_s (_1#_I_s#_N _o_n_l_y) _i_s _i_s_o_l_a_t_e_d
_o_n _e_a_c_h _o_f _t_h_e_s_e _a_t_o_m_s.

[_T_h_e _a_l_t_e_r_n_a_t_i_v_e _e_x_a_m_p_l_e
 #_T
     $_C_O_R_E   _1  _0    _2  _0    _3  _0   $_E_N_D

#_N(_n_o _c_o_r_e_s) _w_o_u_l_d _a_l_l_o_w _a_l_l _N_A_O_s _t_o _b_e _i_n_c_l_u_d_e_d _i_n _t_h_e  _N_B_O
_s_e_a_r_c_h; _t_h_i_s _w_o_u_l_d _b_e _e_q_u_i_v_a_l_e_n_t _t_o _t_h_e _d_e_f_a_u_l_t _t_r_e_a_t_m_e_n_t _i_n
_t_h_e _e_a_r_l_i_e_r _v_e_r_s_i_o_n _o_f _t_h_e  _p_r_o_g_r_a_m  (_s_e_e  _S_e_c_t_i_o_n  _A._1._5).]
#_B_B._4 _T_H_E $_C_H_O_O_S_E _K_E_Y_L_I_S_T (_D_I_R_E_C_T_E_D _N_B_O _S_E_A_R_C_H)#_N

_0 _A $_C_H_O_O_S_E _k_e_y_l_i_s_t _r_e_q_u_e_s_t_s _t_h_a_t _t_h_e _N_B_O _s_e_a_r_c_h _b_e _d_i_r_e_c_t_e_d



                       July 11, 1995





                           - 39 -


_t_o
_f_i_n_d _a _p_a_r_t_i_c_u_l_a_r _L_e_w_i_s  _s_t_r_u_c_t_u_r_e  (`_r_e_s_o_n_a_n_c_e  _s_t_r_u_c_t_u_r_e')
_c_h_o_s_e_n  _b_y  _t_h_e _u_s_e_r.  (_T_h_i_s _i_s _u_s_e_f_u_l _f_o_r _t_e_s_t_i_n_g _t_h_e _a_c_c_u_-
_r_a_c_y _o_f _a_l_t_e_r_n_a_t_i_v_e _r_e_s_o_n_a_n_c_e _s_t_r_u_c_t_u_r_e  _r_e_p_r_e_s_e_n_t_a_t_i_o_n_s  _o_f
_t_h_e  _w_a_v_e_f_u_n_c_t_i_o_n,  _r_e_l_a_t_i_v_e  _t_o _t_h_e _o_p_t_i_m_a_l _L_e_w_i_s _s_t_r_u_c_t_u_r_e
_r_e_t_u_r_n_e_d _i_n _a _f_r_e_e _N_B_O _s_e_a_r_c_h.)   _I_n  _t_h_e  $_C_H_O_O_S_E  _l_i_s_t,  _a
_r_e_s_o_n_a_n_c_e  _s_t_r_u_c_t_u_r_e  _i_s  _s_p_e_c_i_f_i_e_d _b_y _i_n_d_i_c_a_t_i_n_g _w_h_e_r_e _l_o_n_e
_p_a_i_r_s _a_n_d _b_o_n_d_s (_i_n_c_l_u_d_i_n_g _m_u_l_t_i_p_l_e _b_o_n_d_s) _a_r_e _t_o  _b_e  _f_o_u_n_d
_i_n  _t_h_e  _m_o_l_e_c_u_l_e.   _I_n  _s_o_m_e  _c_a_s_e_s,  _t_h_e  _u_s_e_r _m_a_y _w_i_s_h _t_o
_s_p_e_c_i_f_y _o_n_l_y _t_h_e _l_o_c_a_t_i_o_n _o_f _b_o_n_d_s, _l_e_t_t_i_n_g  _t_h_e  _N_B_O  _a_l_g_o_-
_r_i_t_h_m  _s_e_e_k _t_h_e _b_e_s_t _l_o_c_a_t_i_o_n _f_o_r _l_o_n_e _p_a_i_r_s, _b_u_t _i_t _i_s _u_s_u_-
_a_l_l_y _s_a_f_e_s_t _t_o _c_o_m_p_l_e_t_e_l_y _s_p_e_c_i_f_y _t_h_e  _r_e_s_o_n_a_n_c_e  _s_t_r_u_c_t_u_r_e,
_b_o_t_h _l_o_n_e _p_a_i_r_s _a_n_d _b_o_n_d_s.

_0 _T_h_e _f_o_r_m_a_t _o_f _t_h_e $_C_H_O_O_S_E _l_i_s_t _i_s:

_T_h_e _k_e_y_w_o_r_d ``$_C_H_O_O_S_E''

_T_h_e _k_e_y_w_o_r_d ``_A_L_P_H_A'' (_o_n_l_y _f_o_r _o_p_e_n-_s_h_e_l_l _w_a_v_e_f_u_n_c_t_i_o_n)

_I_f _o_n_e-_c_e_n_t_e_r (`_l_o_n_e') _N_B_O_s _a_r_e _t_o _b_e _s_e_a_r_c_h_e_d _f_o_r, _t_y_p_e _t_h_e
_k_e_y_w_o_r_d ``_L_O_N_E'' _f_o_l_l_o_w_e_d _b_y _a _l_i_s_t _o_f _p_a_i_r_s _o_f _n_u_m_b_e_r_s, _t_h_e
_f_i_r_s_t _n_u_m_b_e_r _o_f _e_a_c_h _p_a_i_r _b_e_i_n_g _t_h_e _a_t_o_m_i_c  _c_e_n_t_e_r  _a_n_d  _t_h_e
_s_e_c_o_n_d  _t_h_e _n_u_m_b_e_r _o_f _v_a_l_e_n_c_e _l_o_n_e _p_a_i_r_s _o_n _t_h_a_t _a_t_o_m.  _T_e_r_-
_m_i_n_a_t_e _t_h_e _l_i_s_t _w_i_t_h ``_E_N_D''.  (_N_o_t_e _t_h_a_t _o_n_l_y _t_h_e  _o_c_c_u_p_i_e_d
#_I_v_a_l_e_n_c_e#_N  _l_o_n_e  _p_a_i_r_s _s_h_o_u_l_d _b_e _e_n_t_e_r_e_d, _s_i_n_c_e _t_h_e _n_u_m_b_e_r
_o_f _c_o_r_e _o_r_b_i_t_a_l_s _o_n _e_a_c_h _c_e_n_t_e_r _i_s _p_r_e_s_u_m_e_d _k_n_o_w_n.)

_I_f _t_w_o-_c_e_n_t_e_r (`_b_o_n_d') _N_B_O_s _a_r_e _t_o _b_e _s_e_a_r_c_h_e_d _f_o_r, _t_y_p_e _t_h_e
_k_e_y_w_o_r_d  ``_B_O_N_D'',  _f_o_l_l_o_w_e_d _b_y _t_h_e _l_i_s_t _o_f _b_o_n_d _s_p_e_c_i_f_i_e_r_s,
_a_n_d _t_e_r_m_i_n_a_t_e_d _b_y ``_E_N_D''.  _E_a_c_h _b_o_n_d _s_p_e_c_i_f_i_e_r  _i_s  _o_n_e  _o_f
_t_h_e _l_e_t_t_e_r_s

_s_i_n_g_l_e _b_o_n_d _d_o_u_b_l_e _b_o_n_d _t_r_i_p_l_e _b_o_n_d _q_u_a_d_r_u_p_l_e _b_o_n_d

_f_o_l_l_o_w_e_d _b_y _t_h_e _t_w_o _a_t_o_m_i_c _c_e_n_t_e_r_s _o_f _t_h_e _b_o_n_d (_e._g., ``_D  _9
_1_6'' _f_o_r _a _d_o_u_b_l_e _b_o_n_d _b_e_t_w_e_e_n _a_t_o_m_s _9 _a_n_d _1_6).

_I_f _t_h_r_e_e-_c_e_n_t_e_r _N_B_O_s _a_r_e _t_o _b_e _s_e_a_r_c_h_e_d _f_o_r, _t_y_p_e  _t_h_e  _k_e_y_-
_w_o_r_d  ``_3_C_B_O_N_D'',  _f_o_l_l_o_w_e_d  _b_y _t_h_e _l_i_s_t _o_f _3-_c _b_o_n_d _s_p_e_c_i_f_-
_i_e_r_s, _a_n_d _t_e_r_m_i_n_a_t_e_d _b_y ``_E_N_D''.  _E_a_c_h _3-_c _b_o_n_d _s_p_e_c_i_f_i_e_r _i_s
_a_g_a_i_n  _o_n_e  _o_f  _t_h_e  _l_e_t_t_e_r_s ``_S'' (_s_i_n_g_l_e), ``_D'' (_d_o_u_b_l_e),
``_T'' (_t_r_i_p_l_e), _o_r  ``_Q''  (_q_u_a_d_r_u_p_l_e),  _f_o_l_l_o_w_e_d  _b_y  _t_h_r_e_e
_i_n_t_e_g_e_r_s  _f_o_r  _t_h_e  _t_h_r_e_e _a_t_o_m_i_c _c_e_n_t_e_r_s (_e._g., ``_S _4 _8 _1_0''
_f_o_r _a _s_i_n_g_l_e _t_h_r_e_e-_c_e_n_t_e_r  _b_o_n_d  _4-_8-_1_0).   (_N_o_t_e  _t_h_a_t  _t_h_e
_3_C_B_O_N_D  _k_e_y_w_o_r_d  _o_f _t_h_e $_N_B_O _k_e_y_l_i_s_t _i_s _i_m_p_l_i_c_i_t_l_y _a_c_t_i_v_a_t_e_d
_i_f _3-_c _b_o_n_d_s _a_r_e _i_n_c_l_u_d_e_d _i_n _a $_C_H_O_O_S_E _l_i_s_t.)

_T_h_e _w_o_r_d ``_E_N_D'' _t_o _s_i_g_n_a_l _t_h_e _e_n_d _o_f _t_h_e _l_p_h_a  _s_p_i_n _l_i_s_t.

_T_h_e _k_e_y_w_o_r_d ``_B_E_T_A'' (_f_o_r _o_p_e_n-_s_h_e_l_l _w_a_v_e_f_u_n_c_t_i_o_n_s)

_T_h_e _i_n_p_u_t _f_o_r777777 t99a999999  s99p99i99n99,9999 s99a99_m777777 _f_o_r_m_a_t _a_s  _a_b_o_v_e.   _T_h_e  _o_v_e_r_a_l_l  $_C_H_O_O_S_E
_l_i_s_t _s_h_o_u_l_d _a_l_w_a_y_s _e_n_d _w_i_t_h _t_h_e ``$_E_N_D'' _k_e_y_w_o_r_d.



                       July 11, 1995





                           - 40 -


_T_w_o _e_x_a_m_p_l_e_s _w_i_l_l _s_e_r_v_e _t_o  _i_l_l_u_s_t_r_a_t_e  _t_h_e  $_C_H_O_O_S_E  _f_o_r_m_a_t
(_e_a_c_h  _i_s  _r_a_t_h_e_r  _a_r_t_i_f_i_c_i_a_l,  _i_n_a_s_m_u_c_h  _a_s  _t_h_e  _s_p_e_c_i_f_i_e_d
$_C_H_O_O_S_E _s_t_r_u_c_t_u_r_e _c_o_r_r_e_s_p_o_n_d_s _t_o _t_h_e `_n_o_r_m_a_l' _s_t_r_u_c_t_u_r_e _t_h_a_t
_w_o_u_l_d _b_e _f_o_u_n_d _b_y _t_h_e _N_B_O _p_r_o_g_r_a_m):

_T_h_e  _c_l_o_s_e_d-_s_h_e_l_l  _H-_b_o_n_d_e_d  _c_o_m_p_l_e_x  _F_H9_o_t_s  _C_O,  _w_i_t_h  _a_t_o_m
_n_u_m_b_e_r_i_n_g _F(_1)-_H(_2)9_o_t_s _C(_3)-_O(_4), _m_i_g_h_t _b_e _s_p_e_c_i_f_i_e_d _a_s
 #_T
     $_C_H_O_O_S_E
        _L_O_N_E  _1  _3
              _3  _1
              _4  _1     _E_N_D
        _B_O_N_D  _S  _1  _2
              _T  _3  _4  _E_N_D
     $_E_N_D

#_N_T_h_i_s _w_o_u_l_d _d_i_r_e_c_t _t_h_e _N_B_O _p_r_o_g_r_a_m _t_o _s_e_a_r_c_h _f_o_r _t_h_r_e_e _l_o_n_e
_p_a_i_r_s  _o_n  _a_t_o_m  _F(_1),  _o_n_e _l_o_n_e _p_a_i_r _o_n _a_t_o_m _C(_3), _o_n_e _l_o_n_e
_p_a_i_r _o_n _a_t_o_m _O(_4), _o_n_e _b_o_n_d  _b_e_t_w_e_e_n  _F(_1)-_H(_2),  _a_n_d  _t_h_r_e_e
_b_o_n_d_s _b_e_t_w_e_e_n _C(_3)-_O(_4).

_T_h_e _o_p_e_n-_s_h_e_l_l _F_H9_o_t_s _O#_d_2#_u  _c_o_m_p_l_e_x,  _w_i_t_h  _a_t_o_m  _n_u_m_b_e_r_i_n_g
_F(_1)-_H(_2)#+...#-_O(_3)-_O(_4),  _a_n_d  _w_i_t_h _t_h_e _u_n_p_a_i_r_e_d _e_l_e_c_t_r_o_n_s
_o_n _O#_d_2#_u _b_e_i_n_g _o_f _l_p_h_a  _s_p_i_n, _m_i_g_h_t _b_e _s_p_e_c_i_f_i_e_d _a_s
 #_T
     $_C_H_O_O_S_E
       _A_L_P_H_A
         _L_O_N_E  _1  _3
               _3  _3
               _4  _3     _E_N_D
         _B_O_N_D  _S  _1  _2
               _S  _3  _4  _E_N_D
       _E_N_D
       _B_E_T_A
         _L_O_N_E  _1  _3
               _3  _1
               _4  _1     _E_N_D
         _B_O_N_D  _S  _1  _2
               _T  _3  _4  _E_N_D
       _E_N_D
     $_E_N_D

#_N_N_o_t_e _t_h_a_t _t_h_i_s _e_x_a_m_p_l_e _i_n_c_o_r_p_o_r_a_t_e_s  _t_h_e  _i_d_e_a  _o_f  ``_d_i_f_-
_f_e_r_e_n_t  _L_e_w_i_s  _s_t_r_u_c_t_u_r_e_s _f_o_r _d_i_f_f_e_r_e_n_t _s_p_i_n_s,'' _w_i_t_h _a _d_i_s_-
_t_i_n_c_t _p_a_t_t_e_r_n _o_f _l_o_c_a_l_i_z_e_d _1-_c  (`_l_o_n_e')  _a_n_d  _2-_c  (`_b_o_n_d')
_f_u_n_c_t_i_o_n_s  _f_o_r  _l_p_h_a   _a_n_d7777 t99a999999  s99p99i99n99.7777 _0 _A_s _w_i_t_h _o_t_h_e_r _k_e_y_l_i_s_t_s, _t_h_e
$_C_H_O_O_S_E _k_e_y_l_i_s_t _c_a_n _b_e _c_o_n_d_e_n_s_e_d  _t_o  _a  _s_m_a_l_l_e_r  _n_u_m_b_e_r  _o_f
_l_i_n_e_s,  _a_s  _l_o_n_g  _a_s _n_o _l_i_n_e _i_s _s_h_a_r_e_d _w_i_t_h _a_n_o_t_h_e_r _k_e_y_l_i_s_t.
_T_h_e _o_r_d_e_r _o_f _k_e_y_w_o_r_d_s _w_i_t_h_i_n _t_h_e $_C_H_O_O_S_E _k_e_y_l_i_s_t  _s_h_o_u_l_d  _b_e
_a_s  _s_h_o_w_n  _a_b_o_v_e (_i._e., _A_L_P_H_A _b_e_f_o_r_e _B_E_T_A, _L_O_N_E _b_e_f_o_r_e _B_O_N_D,
_e_t_c.), _b_u_t _t_h_e _o_r_d_e_r _o_f _e_n_t_r_i_e_s _w_i_t_h_i_n _a _L_O_N_E _o_r  _B_O_N_D  _l_i_s_t
_i_s  _i_m_m_a_t_e_r_i_a_l.   _A  $_C_O_R_E _k_e_y_l_i_s_t (_i_f _p_r_e_s_e_n_t) _m_u_s_t _p_r_e_c_e_d_e
_t_h_e $_C_H_O_O_S_E _l_i_s_t.  #_B_B._5 _T_H_E  $_D_E_L  _K_E_Y_L_I_S_T  (_N_B_O  _E_N_E_R_G_E_T_I_C
_A_N_A_L_Y_S_I_S)#_N



                       July 11, 1995





                           - 41 -


#_I_B._5._1 _I_n_t_r_o_d_u_c_t_i_o_n _t_o _N_B_O _E_n_e_r_g_e_t_i_c _A_n_a_l_y_s_i_s#_N

_0 _T_h_e _f_o_u_r_t_h _a_n_d _f_i_n_a_l _t_y_p_e  _o_f  _k_e_y_l_i_s_t  _i_s  _a  `_d_e_l_e_t_i_o_n_s'
($_D_E_L)  _k_e_y_l_i_s_t,  _t_o  _a_c_t_i_v_a_t_e _N_B_O _e_n_e_r_g_e_t_i_c _a_n_a_l_y_s_i_s.  _T_h_i_s
_a_n_a_l_y_s_i_s _i_s _p_e_r_f_o_r_m_e_d _b_y (_1) _d_e_l_e_t_i_n_g _s_p_e_c_i_f_i_e_d _e_l_e_m_e_n_t_s (_o_r
_b_l_o_c_k_s  _o_f _e_l_e_m_e_n_t_s) _f_r_o_m _t_h_e _N_B_O _F_o_c_k _m_a_t_r_i_x, (_2) _d_i_a_g_o_n_a_l_-
_i_z_i_n_g _t_h_i_s _n_e_w _F_o_c_k _m_a_t_r_i_x _t_o _o_b_t_a_i_n _a _n_e_w  _d_e_n_s_i_t_y  _m_a_t_r_i_x,
_a_n_d  (_3) _p_a_s_s_i_n_g _t_h_i_s _d_e_n_s_i_t_y _m_a_t_r_i_x _t_o _t_h_e _S_C_F _r_o_u_t_i_n_e_s _f_o_r
_a _s_i_n_g_l_e _p_a_s_s _t_h_r_o_u_g_h _t_h_e _S_C_F _e_n_e_r_g_y _e_v_a_l_u_a_t_o_r.  _T_h_e _d_i_f_f_e_r_-
_e_n_c_e  _b_e_t_w_e_e_n  _t_h_i_s  `_d_e_l_e_t_i_o_n'  _e_n_e_r_g_y _a_n_d _t_h_e _o_r_i_g_i_n_a_l _S_C_F
_e_n_e_r_g_y _p_r_o_v_i_d_e_s _a _u_s_e_f_u_l _m_e_a_s_u_r_e _o_f _t_h_e _e_n_e_r_g_y  _c_o_n_t_r_i_b_u_t_i_o_n
_o_f  _t_h_e _d_e_l_e_t_e_d _t_e_r_m_s.  _S_i_n_c_e _a _F_o_c_k _m_a_t_r_i_x _i_s _r_e_q_u_i_r_e_d, _t_h_e
_e_n_e_r_g_e_t_i_c _a_n_a_l_y_s_i_s _i_s _p_e_r_f_o_r_m_e_d _f_o_r _R_H_F  _a_n_d  _U_H_F  _w_a_v_e_f_u_n_c_-
_t_i_o_n_s _o_n_l_y.

_0 _I_n_p_u_t _f_o_r _t_h_e _N_B_O _e_n_e_r_g_e_t_i_c _a_n_a_l_y_s_i_s _i_s _t_h_r_o_u_g_h  _t_h_e  $_D_E_L
_k_e_y_l_i_s_t,  _w_h_i_c_h  _s_p_e_c_i_f_i_e_s  _t_h_e  _d_e_l_e_t_i_o_n_s  _t_o _b_e _p_e_r_f_o_r_m_e_d.
_M_u_l_t_i_p_l_e _a_n_a_l_y_s_e_s (_d_e_l_e_t_i_o_n_s) _c_a_n _b_e _p_e_r_f_o_r_m_e_d _d_u_r_i_n_g _a _s_i_n_-
_g_l_e  _j_o_b,  _w_i_t_h  _e_a_c_h  _d_e_l_e_t_i_o_n _i_n_c_l_u_d_e_d _i_n _t_h_e _o_v_e_r_a_l_l $_D_E_L
_k_e_y_l_i_s_t.  _T_h_e _n_i_n_e _d_i_s_t_i_n_c_t _t_y_p_e_s  _o_f  _d_e_l_e_t_i_o_n_s  _i_n_p_u_t  _a_r_e
_d_e_s_c_r_i_b_e_d _i_n _S_e_c_t_i_o_n _B._5._2 _b_e_l_o_w.

_0 _T_h_e _d_e_l_e_t_i_o_n_s _k_e_y_l_i_s_t _b_e_g_i_n_s _w_i_t_h  _t_h_e  ``$_D_E_L''  _k_e_y_w_o_r_d.
_F_o_r _t_h_e _a_n_a_l_y_s_i_s _o_f _U_H_F _w_a_v_e_f_u_n_c_t_i_o_n_s, _t_h_e _d_e_l_e_t_i_o_n_s _f_o_r _t_h_e
_l_p_h_a  _a_n_d777777777777 t99a999999  s99p99i99n9999 m99a99n99i99f99o99l99d99s9999 m99u99s99t9999 _b777777777777 _s_e_p_a_r_a_t_e_l_y _s_p_e_c_i_f_i_e_d (_s_e_e  _S_e_c_t_i_o_n  _B._5._3).
_O_t_h_e_r_w_i_s_e, _t_h_e _i_n_p_u_t _f_o_r _c_l_o_s_e_d _s_h_e_l_l_s _R_H_F _a_n_d _U_H_F _i_s _i_d_e_n_t_-
_i_c_a_l.  _T_h_e _i_n_p_u_t _i_s _f_r_e_e _f_o_r_m_a_t _a_n_d _t_h_e _i_n_p_u_t _f_o_r  _a  _s_i_n_g_l_e
_d_e_l_e_t_i_o_n  _c_a_n  _b_e _s_p_r_e_a_d _o_v_e_r _a_s _m_a_n_y _l_i_n_e_s _a_s _d_e_s_i_r_e_d.  _T_h_e
_d_e_s_i_r_e_d _d_e_l_e_t_i_o_n_s _s_h_o_u_l_d _b_e  _l_i_s_t_e_d  _o_n_e  _a_f_t_e_r  _t_h_e  _o_t_h_e_r.
_A_f_t_e_r  _t_h_e  _l_a_s_t _d_e_l_e_t_i_o_n, _t_h_e _w_o_r_d ``$_E_N_D'' _s_i_g_n_a_l_s _t_h_e _e_n_d
_o_f _t_h_e _k_e_y_l_i_s_t.


|<<_3//_1_8//_7_2//+_0//+_1_3>>|7______________________99______________________

#_B_W_A_R_N_I_N_G#_N

_I_f _s_y_m_m_e_t_r_y _i_s _u_s_e_d, _o_n_e _m_u_s_t _b_e _c_a_r_e_f_u_l _t_o  _o_n_l_y  _d_o  _d_e_l_e_-
_t_i_o_n_s  _t_h_a_t  _w_i_l_l  _p_r_e_s_e_r_v_e  _t_h_e  _s_y_m_m_e_t_r_y _o_f _t_h_e _e_l_e_c_t_r_o_n_i_c
_w_a_v_e_f_u_n_c_t_i_o_n!!  _I_f _t_h_i_s _i_s _n_o_t _d_o_n_e, _t_h_e _e_n_e_r_g_y _o_f _t_h_e _d_e_l_e_-
_t_i_o_n  _w_i_l_l  _b_e  _i_n_c_o_r_r_e_c_t  _b_e_c_a_u_s_e _t_h_e _a_s_s_u_m_p_t_i_o_n _i_s _m_a_d_e _i_n
_e_v_a_l_u_a_t_i_n_g _t_h_e  _e_n_e_r_g_y  _t_h_a_t  _t_h_e  _o_r_i_g_i_n_a_l  _s_y_m_m_e_t_r_y  _s_t_i_l_l
_e_x_i_s_t_s, _a_n_d _t_h_e _v_a_r_i_a_t_i_o_n_a_l _p_r_i_n_c_i_p_l_e _m_a_y _b_e _v_i_o_l_a_t_e_d.  (_F_o_r
_e_x_a_m_p_l_e, _i_f _s_y_m_m_e_t_r_y _i_s _u_s_e_d _f_o_r _e_t_h_a_n_e, _i_s  _i_s  _p_e_r_m_i_s_s_i_b_l_e
_t_o  _d_o _a ``_N_O_S_T_A_R'' _d_e_l_e_t_i_o_n, _b_u_t _n_o_t _t_h_e _d_e_l_e_t_i_o_n _o_f _a _s_i_n_-
_g_l_e _C-_H _a_n_t_i_b_o_n_d.)  _T_h_e _r_e_m_e_d_y _i_s _n_o_t _t_o _u_s_e _s_y_m_m_e_t_r_y _i_n _t_h_e
_S_C_F _c_a_l_c_u_l_a_t_i_o_n.


_0 _I_n _d_e_s_c_r_i_b_i_n_g _t_h_e _d_e_l_e_t_i_o_n _t_y_p_e_s, _u_s_e _i_s _m_a_d_e _o_f _t_h_e _t_e_r_m_s
``_m_o_l_e_c_u_l_a_r  _u_n_i_t'' _a_n_d ``_c_h_e_m_i_c_a_l _f_r_a_g_m_e_n_t.''  _T_h_e _N_B_O _p_r_o_-
_g_r_a_m _l_o_o_k_s _a_t _t_h_e _c_h_e_m_i_c_a_l _b_o_n_d_i_n_g _p_a_t_t_e_r_n _p_r_o_d_u_c_e_d  _b_y  _t_h_e
_b_o_n_d_i_n_g  _N_B_O_s  _a_n_d  _i_d_e_n_t_i_f_i_e_s  _t_h_e _g_r_o_u_p_s _o_f _a_t_o_m_s _t_h_a_t _a_r_e
_l_i_n_k_e_d _t_o_g_e_t_h_e_r _i_n  _d_i_s_t_i_n_c_t  ``_m_o_l_e_c_u_l_a_r  _u_n_i_t_s''  (_u_s_u_a_l_l_y



                       July 11, 1995





                           - 42 -


_s_y_n_o_n_y_m_o_u_s
_w_i_t_h ``_m_o_l_e_c_u_l_e_s'' _i_n _t_h_e _c_h_e_m_i_c_a_l _s_e_n_s_e).  _T_h_e  _f_i_r_s_t  _a_t_o_m
_t_h_a_t _i_s _n_o_t _i_n _m_o_l_e_c_u_l_a_r _u_n_i_t _1 _w_i_l_l _b_e _i_n _m_o_l_e_c_u_l_a_r _u_n_i_t _2,
_a_n_d _s_o _f_o_r_t_h.  _F_o_r _e_x_a_m_p_l_e, _i_f _t_h_e _l_i_s_t _o_f  _a_t_o_m_s  _i_s  _C(_1),
_H(_2),  _F(_3),  _O(_4), _a_n_d _b_o_n_d_i_n_g _N_B_O_s _a_r_e _f_o_u_n_d _b_e_t_w_e_e_n _C(_1)-
_O(_4) _a_n_d _H(_2)-_F(_3), _t_h_e_n _m_o_l_e_c_u_l_a_r _u_n_i_t _1  _w_i_l_l  _b_e  _C_O  _a_n_d
_m_o_l_e_c_u_l_a_r  _u_n_i_t  _2  _w_i_l_l  _b_e _H_F.  _A ``_c_h_e_m_i_c_a_l _f_r_a_g_m_e_n_t'' _i_s
_t_a_k_e_n _t_o _b_e _a_n_y _s_u_b_s_e_t _o_f _t_h_e _a_t_o_m_s, _u_s_u_a_l_l_y (_b_u_t _n_o_t _n_e_c_e_s_-
_s_a_r_i_l_y)  _i_n  _t_h_e  _s_a_m_e  _m_o_l_e_c_u_l_a_r _u_n_i_t, _a_n_d _u_s_u_a_l_l_y (_b_u_t _n_o_t
_n_e_c_e_s_s_a_r_i_l_y) _c_o_n_n_e_c_t_e_d _b_y _b_o_n_d _N_B_O_s.  _T_y_p_i_c_a_l_l_y, _a  _c_h_e_m_i_c_a_l
_f_r_a_g_m_e_n_t  _m_i_g_h_t  _b_e  _s_p_e_c_i_f_i_e_d _t_o _b_e _a _s_i_n_g_l_e _a_t_o_m, _t_h_e _f_o_u_r
_a_t_o_m_s _o_f _a _m_e_t_h_y_l _g_r_o_u_p, _o_r _a_n_y _o_t_h_e_r `_r_a_d_i_c_a_l' _o_f _a _m_o_l_e_c_u_-
_l_a_r _u_n_i_t, _i_d_e_n_t_i_f_i_e_d _b_y _g_i_v_i_n_g _t_h_e _a_t_o_m _n_u_m_b_e_r_s _o_f _w_h_i_c_h _t_h_e
_f_r_a_g_m_e_n_t _c_o_n_s_i_s_t_s.  #_I_B._5._2 _T_h_e _N_i_n_e _D_e_l_e_t_i_o_n _T_y_p_e_s#_N

_0 _T_h_e _k_e_y_w_o_r_d_s _a_n_d  _f_o_r_m_a_t  _t_o  _s_p_e_c_i_f_y  _e_a_c_h  _o_f  _t_h_e  _n_i_n_e
_a_l_l_o_w_e_d _d_e_l_e_t_i_o_n _t_y_p_e_s _a_r_e _d_e_s_c_r_i_b_e_d _b_e_l_o_w:


#_(_1) _D_e_l_e_t_i_o_n _o_f _e_n_t_i_r_e _o_r_b_i_t_a_l_s.#/

_T_h_i_s _i_s _c_a_l_l_e_d _f_o_r _b_y _t_y_p_i_n_g ``_D_E_L_E_T_E'', _t_h_e_n _t_h_e _n_u_m_b_e_r  _o_f
_o_r_b_i_t_a_l_s  _t_o  _b_e  _d_e_l_e_t_e_d,  _t_h_e_n _t_h_e _k_e_y_w_o_r_d ``_O_R_B_I_T_A_L'' (_o_r
``_O_R_B_I_T_A_L_S''), _t_h_e_n _t_h_e _l_i_s_t _o_f _t_h_e _o_r_b_i_t_a_l_s _t_o _b_e _d_e_l_e_t_e_d.

  _E_x_a_m_p_l_e:     #_T_D_E_L_E_T_E  _3  _O_R_B_I_T_A_L_S  _1_5  _1_8  _2_9

#_N[_S_e_e _a_l_s_o _d_e_l_e_t_i_o_n _t_y_p_e_s (_4) _a_n_d (_7) _f_o_r _d_e_l_e_t_i_n_g _s_e_t_s  _o_f
_o_r_b_i_t_a_l_s.]

|<<_3//_1_8//_7_2//+_0//+_1_1>>|7______________________99______________________

#_B_W_A_R_N_I_N_G#_N

_T_h_e ``_s_i_n_g_l_e-_p_a_s_s'' _m_e_t_h_o_d _o_f _e_v_a_l_u_a_t_i_n_g  _d_e_l_e_t_i_o_n  _e_n_e_r_g_i_e_s
_i_s  _a_p_p_r_o_p_r_i_a_t_e  _o_n_l_y  _f_o_r  _d_e_l_e_t_i_o_n_s  _o_f  #_I_l_o_w#_N-_o_c_c_u_p_a_n_c_y
(_n_o_n-_L_e_w_i_s) _o_r_b_i_t_a_l_s, _f_o_r _w_h_i_c_h _t_h_e _l_o_s_s _o_f _s_e_l_f-_c_o_n_s_i_s_t_e_n_c_y
_i_n  _t_h_e  _C_o_u_l_o_m_b _a_n_d _e_x_c_h_a_n_g_e _p_o_t_e_n_t_i_a_l_s (_d_u_e _t_o _r_e_d_i_s_t_r_i_b_u_-
_t_i_o_n _o_f _t_h_e _e_l_e_c_t_r_o_n _d_e_n_s_i_t_y _o_f _d_e_l_e_t_e_d _o_r_b_i_t_a_l_s)  _i_s  _s_m_a_l_l
_c_o_m_p_a_r_e_d _t_o _t_h_e _n_e_t _e_n_e_r_g_y _c_h_a_n_g_e _o_f _d_e_l_e_t_i_o_n.  _I_t _i_s _f_u_n_d_a_-
_m_e_n_t_a_l_l_y  _e_r_r_o_n_e_o_u_s  _t_o  _d_e_l_e_t_e  #_I_h_i_g_h#_N-_o_c_c_u_p_a_n_c_y  (_L_e_w_i_s)
_o_r_b_i_t_a_l_s _b_y _t_h_i_s _p_r_o_c_e_d_u_r_e.



#_(_2) _D_e_l_e_t_i_o_n _o_f _s_p_e_c_i_f_i_c _F_o_c_k _m_a_t_r_i_x _e_l_e_m_e_n_t_s.#/

_T_h_i_s _i_s _c_a_l_l_e_d _f_o_r _b_y _t_y_p_i_n_g ``_D_E_L_E_T_E'', _t_h_e_n _t_h_e _n_u_m_b_e_r  _o_f
_e_l_e_m_e_n_t_s  _t_o  _b_e  _d_e_l_e_t_e_d,  _t_h_e_n _t_h_e _k_e_y_w_o_r_d ``_E_L_E_M_E_N_T'' (_o_r
``_E_L_E_M_E_N_T_S''), _t_h_e_n _t_h_e _l_i_s_t _o_f _t_h_e _e_l_e_m_e_n_t_s _t_o  _b_e  _d_e_l_e_t_e_d
(_e_a_c_h _a_s _a _p_a_i_r _o_f _i_n_t_e_g_e_r_s).

  _E_x_a_m_p_l_e:     #_T_D_E_L_E_T_E  _3  _E_L_E_M_E_N_T_S  _1 _1_5  _3 _1_9  _2_3 _2




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                           - 43 -


#_N_T_h_i_s _e_x_a_m_p_l_e _w_o_u_l_d _r_e_s_u_l_t _i_n _t_h_e _z_e_r_o_i_n_g _o_f _t_h_e  _f_o_l_l_o_w_i_n_g
_F_o_c_k  _m_a_t_r_i_x  _e_l_e_m_e_n_t_s:   (_1,_1_5),  (_1_5,_1),  (_3,_1_9),  (_1_9,_3),
(_2_3,_2), (_2,_2_3).  [_S_e_e _a_l_s_o _d_e_l_e_t_i_o_n  _t_y_p_e_s  (_3),  (_5),  (_6),
(_8), (_9) _f_o_r _d_e_l_e_t_i_n_g _s_e_t_s _o_f _e_l_e_m_e_n_t_s.]


#_(_3) _D_e_l_e_t_i_o_n _o_f _o_f_f-_d_i_a_g_o_n_a_l _b_l_o_c_k_s _o_f _t_h_e _F_o_c_k _m_a_t_r_i_x.#/

_E_a_c_h _b_l_o_c_k _i_s _s_p_e_c_i_f_i_e_d _b_y _t_w_o _s_e_t_s  _o_f  _o_r_b_i_t_a_l_s,  _a_n_d  _a_l_l
_F_o_c_k  _m_a_t_r_i_x  _e_l_e_m_e_n_t_s  _i_n _c_o_m_m_o_n _b_e_t_w_e_e_n _t_h_e_s_e _t_w_o _s_e_t_s _a_r_e
_s_e_t _t_o _z_e_r_o.  _T_h_i_s _i_s _c_a_l_l_e_d _f_o_r _b_y  _t_y_p_i_n_g  ``_Z_E_R_O'',  _t_h_e_n
_t_h_e  _n_u_m_b_e_r  _o_f  _o_f_f-_d_i_a_g_o_n_a_l _b_l_o_c_k_s _t_o _b_e _z_e_r_o_e_d, _a_n_d _t_h_e_n,
_f_o_r _e_a_c_h _b_l_o_c_k, _t_h_e _f_o_l_l_o_w_i_n_g:

(_1) _t_h_e _d_i_m_e_n_s_i_o_n_s _o_f  _t_h_e  _b_l_o_c_k,  _s_e_p_a_r_a_t_e_d  _b_y  _t_h_e  _w_o_r_d
``_B_Y'' (_e._g., ``_6 _B_Y _3'' _i_f _t_h_e _f_i_r_s_t _s_e_t _h_a_s _6 _o_r_b_i_t_a_l_s _a_n_d
_t_h_e _s_e_c_o_n_d _s_e_t _h_a_s _3 _o_r_b_i_t_a_l_s);

(_2) _t_h_e _l_i_s_t _o_f _o_r_b_i_t_a_l_s _i_n _t_h_e _f_i_r_s_t _s_e_t;

(_3) _t_h_e _l_i_s_t _o_f _o_r_b_i_t_a_l_s _i_n _t_h_e _s_e_c_o_n_d _s_e_t.

_A_n _e_x_a_m_p_l_e _i_s _s_h_o_w_n _b_e_l_o_w:
 #_T
     _Z_E_R_O  _2  _B_L_O_C_K_S  _2  _B_Y  _5
                               _3  _4
                               _9  _1_0  _1_1  _1_4  _1_9
                      _3  _B_Y  _2
                               _1  _2  _7
                              _2_0  _2_4

#_N_T_h_i_s _w_i_l_l _s_e_t _t_h_e _f_o_l_l_o_w_i_n_g _F_o_c_k _m_a_t_r_i_x _e_l_e_m_e_n_t_s _t_o _z_e_r_o:

(_3,_9),  (_3,_1_0),  (_3,_1_1),  (_3,_1_4),  (_3,_1_9),  (_9,_3),   (_1_0,_3),
(_1_1,_3),  (_1_4,_3),  (_1_9,_3),  (_4,_9),  (_4,_1_0),  (_4,_1_1),  (_4,_1_4),
(_4,_1_9),  (_9,_4),  (_1_0,_4),  (_1_1,_4),  (_1_4,_4),  (_1_9,_4),  (_1,_2_0),
(_1,_2_4),  (_2,_2_0),  (_2,_2_4),  (_7,_2_0),  (_7,_2_4)  (_2_0,_1),  (_2_4,_1),
(_2_0,_2), (_2_4,_2), (_2_0,_7), (_2_4,_7)

[_U_s_u_a_l_l_y, _i_n _s_t_u_d_y_i_n_g  _t_h_e  _t_o_t_a_l  _d_e_l_o_c_a_l_i_z_a_t_i_o_n  _f_r_o_m  _o_n_e
_m_o_l_e_c_u_l_a_r _u_n_i_t _t_o _a_n_o_t_h_e_r, _i_t _i_s _m_u_c_h _e_a_s_i_e_r _t_o _u_s_e _d_e_l_e_t_i_o_n
_t_y_p_e (_8) _b_e_l_o_w.  _S_i_m_i_l_a_r_l_y, _i_n _s_t_u_d_y_i_n_g _t_h_e _t_o_t_a_l  _d_e_l_o_c_a_l_i_-
_z_a_t_i_o_n  _f_r_o_m  _o_n_e _c_h_e_m_i_c_a_l _f_r_a_g_m_e_n_t _t_o _a_n_o_t_h_e_r, _i_t _i_s _e_a_s_i_e_r
_t_o _u_s_e _d_e_l_e_t_i_o_n _t_y_p_e (_9).]


#_(_4) _D_e_l_e_t_i_o_n _o_f _a_l_l _R_y_d_b_e_r_g _a_n_d _a_n_t_i_b_o_n_d _o_r_b_i_t_a_l_s.#/

_T_h_e _R_y_d_b_e_r_g _a_n_d _a_n_t_i_b_o_n_d  _o_r_b_i_t_a_l_s  _a_r_e  _t_h_e  _n_o_n-_L_e_w_i_s  _N_B_O
_o_r_b_i_t_a_l_s  _t_h_a_t  _h_a_v_e _s_t_a_r_s _i_n _t_h_e_i_r _l_a_b_e_l_s (_R_Y*, _B_D*) _i_n _t_h_e
_N_B_O _a_n_a_l_y_s_i_s _o_u_t_p_u_t.  _T_o _d_e_l_e_t_e _a_l_l _t_h_e_s_e  _o_r_b_i_t_a_l_s,  _s_i_m_p_l_y
_e_n_t_e_r ``_N_O_S_T_A_R''.  _T_h_e _r_e_s_u_l_t _o_f _t_h_i_s _d_e_l_e_t_i_o_n _i_s _t_h_e _e_n_e_r_g_y
_o_f _t_h_e _i_d_e_a_l_i_z_e_d _N_B_O _n_a_t_u_r_a_l _L_e_w_i_s _s_t_r_u_c_t_u_r_e, _w_i_t_h _a_l_l _L_e_w_i_s
_N_B_O_s  _d_o_u_b_l_y  _o_c_c_u_p_i_e_d.   (_U_n_l_i_k_e  _o_t_h_e_r _d_e_l_e_t_i_o_n_s, _i_n _w_h_i_c_h



                       July 11, 1995





                           - 44 -


_t_h_e_r_e
_i_s _a _s_l_i_g_h_t _l_o_s_s _o_f _v_a_r_i_a_t_i_o_n_a_l _s_e_l_f-_c_o_n_s_i_s_t_e_n_c_y _d_u_e _t_o  _t_h_e
_r_e_d_i_s_t_r_i_b_u_t_e_d  _o_c_c_u_p_a_n_c_y _o_f _t_h_e _d_e_l_e_t_e_d _o_r_b_i_t_a_l_s, _t_h_e _r_e_s_u_l_t
_o_f _a ``_N_O_S_T_A_R'' _d_e_l_e_t_i_o_n _c_o_r_r_e_s_p_o_n_d_s _r_i_g_o_r_o_u_s_l_y _t_o _t_h_e _v_a_r_i_-
_a_t_i_o_n_a_l _e_x_p_e_c_t_a_t_i_o_n _v_a_l_u_e _o_f _t_h_e _d_e_t_e_r_m_i_n_a_n_t _o_f _d_o_u_b_l_y _o_c_c_u_-
_p_i_e_d _L_e_w_i_s _N_B_O_s).


#_(_5) _D_e_l_e_t_i_o_n _o_f _a_l_l _v_i_c_i_n_a_l _d_e_l_o_c_a_l_i_z_a_t_i_o_n_s.#/

_T_o _d_e_l_e_t_e _a_l_l _F_o_c_k _m_a_t_r_i_x _e_l_e_m_e_n_t_s _b_e_t_w_e_e_n  _L_e_w_i_s  _N_B_O_s  _a_n_d
_t_h_e _v_i_c_i_n_a_l _n_o_n-_L_e_w_i_s _N_B_O_s, _s_i_m_p_l_y _e_n_t_e_r ``_N_O_V_I_C''.


#_(_6) _D_e_l_e_t_i_o_n _o_f _a_l_l _g_e_m_i_n_a_l _d_e_l_o_c_a_l_i_z_a_t_i_o_n_s.#/

_T_o _d_e_l_e_t_e _a_l_l _F_o_c_k _m_a_t_r_i_x _e_l_e_m_e_n_t_s _b_e_t_w_e_e_n  _L_e_w_i_s  _N_B_O_s  _a_n_d
_t_h_e _g_e_m_i_n_a_l _n_o_n-_L_e_w_i_s _N_B_O_s, _s_i_m_p_l_y _e_n_t_e_r ``_N_O_G_E_M''.


#_(_7) _D_e_l_e_t_i_o_n _o_f _a_l_l _s_t_a_r_r_e_d (_a_n_t_i_b_o_n_d/_R_y_d_b_e_r_g) _o_r_b_i_t_a_l_s _o_n
_a _p_a_r_t_i_c_u_l_a_r _m_o_l_e_c_u_l_a_r _u_n_i_t.#/

_T_h_i_s _i_s _c_a_l_l_e_d _f_o_r _b_y _t_y_p_i_n_g ``_D_E_S_T_A_R'', _t_h_e_n _t_h_e _n_u_m_b_e_r  _o_f
_m_o_l_e_c_u_l_a_r _u_n_i_t_s _t_o _b_e _d_e#|_s_t_a_r_r_e_d, _t_h_e_n _t_h_e _k_e_y_w_o_r_d ``_U_N_I_T''
(_o_r ``_U_N_I_T_S''), _t_h_e_n _t_h_e _l_i_s_t _o_f _u_n_i_t_s.

  _E_x_a_m_p_l_e:     #_T_D_E_S_T_A_R  _2  _U_N_I_T_S  _3  _4
 #_N

#_(_8) _Z_e_r_o_i_n_g _a_l_l _d_e_l_o_c_a_l_i_z_a_t_i_o_n _f_r_o_m _o_n_e _m_o_l_e_c_u_l_a_r _u_n_i_t  _t_o
_a_n_o_t_h_e_r.#/

_T_h_i_s _i_s _c_a_l_l_e_d _f_o_r _b_y _t_y_p_i_n_g ``_Z_E_R_O'', _t_h_e_n  _t_h_e  _n_u_m_b_e_r  _o_f
_d_e_l_o_c_a_l_i_z_a_t_i_o_n_s _t_o _z_e_r_o, _t_h_e_n _t_h_e _k_e_y_w_o_r_d ``_D_E_L_O_C_A_L_I_Z_A_T_I_O_N''
(_c_a_n _b_e _a_b_b_r_e_v_i_a_t_e_d _t_o ``_D_E_L_O_C''), _a_n_d _t_h_e_n, _f_o_r _e_a_c_h  _d_e_l_o_-
_c_a_l_i_z_a_t_i_o_n, _t_h_e _w_o_r_d ``_F_R_O_M'', _t_h_e _n_u_m_b_e_r _o_f _t_h_e _d_o_n_o_r _u_n_i_t,
_t_h_e _w_o_r_d ``_T_O'', _a_n_d _t_h_e _n_u_m_b_e_r _o_f _t_h_e _a_c_c_e_p_t_o_r _u_n_i_t.

  _E_x_a_m_p_l_e:     #_T_Z_E_R_O  _2  _D_E_L_O_C  _F_R_O_M _1 _T_O _2   _F_R_O_M _2 _T_O _1

#_N_T_h_e _a_b_o_v_e _e_x_a_m_p_l_e _w_o_u_l_d _z_e_r_o #_I_a_l_l#_N _i_n_t_e_r_m_o_l_e_c_u_l_a_r  _d_e_l_o_-
_c_a_l_i_z_a_t_i_o_n_s _b_e_t_w_e_e_n _u_n_i_t_s _1 _a_n_d _2 (_i._e., _b_o_t_h _17 _a_r_r  _2 _a_n_d _2
7_a_r_r  _1).  _T_h_e _e_f_f_e_c_t _i_s _t_o _r_e_m_o_v_e _a_l_l _F_o_c_k  _m_a_t_r_i_x  _e_l_e_m_e_n_t_s
_b_e_t_w_e_e_n  _h_i_g_h-_o_c_c_u_p_a_n_c_y  (_c_o_r_e/_l_o_n_e  _p_a_i_r/_b_o_n_d)  _N_B_O_s _o_f _t_h_e
_d_o_n_o_r _u_n_i_t _t_o _t_h_e _l_o_w-_o_c_c_u_p_a_n_c_y (_a_n_t_i_b_o_n_d/_R_y_d_b_e_r_g)  _N_B_O_s  _o_f
_t_h_e  _a_c_c_e_p_t_o_r _u_n_i_t.  _T_h_e _d_o_n_o_r _a_n_d _a_c_c_e_p_t_o_r _u_n_i_t_s _m_a_y _b_e _t_h_e
_s_a_m_e.


#_(_9) _Z_e_r_o_i_n_g _a_l_l _d_e_l_o_c_a_l_i_z_a_t_i_o_n _f_r_o_m _o_n_e _c_h_e_m_i_c_a_l  _f_r_a_g_m_e_n_t
_t_o _a_n_o_t_h_e_r.#/

_T_h_i_s _i_s _c_a_l_l_e_d _f_o_r _b_y _t_y_p_i_n_g ``_Z_E_R_O'', _t_h_e_n  _t_h_e  _n_u_m_b_e_r  _o_f



                       July 11, 1995





                           - 45 -


_i_n_t_e_r-_f_r_a_g_m_e_n_t
_d_e_l_o_c_a_l_i_z_a_t_i_o_n_s  _t_o  _b_e  _z_e_r_o_e_d,  _t_h_e_n  _t_h_e   _w_o_r_d_s   ``_A_T_O_M
_B_L_O_C_K_S'', _a_n_d _t_h_e_n, _f_o_r _e_a_c_h _d_e_l_o_c_a_l_i_z_a_t_i_o_n, _t_h_e _f_o_l_l_o_w_i_n_g:

(_1) _t_h_e _n_u_m_b_e_r _o_f _a_t_o_m_s _i_n _t_h_e _t_w_o _f_r_a_g_m_e_n_t_s,  _s_e_p_a_r_a_t_e_d  _b_y
_t_h_e  _w_o_r_d  ``_B_Y''  (_e._g., ``_6  _B_Y  _3'' _i_f _t_h_e _f_i_r_s_t _f_r_a_g_m_e_n_t
_h_a_s _6 _a_t_o_m_s _a_n_d _t_h_e _s_e_c_o_n_d _h_a_s _3 _a_t_o_m_s);

(_2) _t_h_e _l_i_s_t _o_f _a_t_o_m_s _i_n _t_h_e _f_i_r_s_t _f_r_a_g_m_e_n_t;

(_3) _t_h_e _l_i_s_t _o_f _a_t_o_m_s _i_n _t_h_e _s_e_c_o_n_d _f_r_a_g_m_e_n_t.

_F_o_r _e_x_a_m_p_l_e, _t_o _z_e_r_o _a_l_l _d_e_l_o_c_a_l_i_z_a_t_i_o_n_s _b_e_t_w_e_e_n  _t_h_e  _f_r_a_g_-
_m_e_n_t_s  _d_e_f_i_n_e_d _b_y _a_t_o_m_s (_1,_2) _a_n_d _b_y _a_t_o_m_s (_3,_4,_5), _t_h_e $_D_E_L
_e_n_t_r_i_e_s _w_o_u_l_d _b_e
 #_T
     _Z_E_R_O  _2  _A_T_O_M _B_L_O_C_K_S
              _2  _B_Y  _3
                       _1  _2
                       _3  _4  _5
              _3  _B_Y  _2
                       _3  _4  _5
                       _1  _2

#_N_I_n _t_h_i_s _e_x_a_m_p_l_e, _t_h_e _f_i_r_s_t _b_l_o_c_k  _r_e_m_o_v_e_s  _t_h_e  (_1,_2)7  _a_r_r
(_3,_4,_5)   _d_e_l_o_c_a_l_i_z_a_t_i_o_n_s,  _w_h_i_l_e  _t_h_e  _s_e_c_o_n_d  _r_e_m_o_v_e_s  _t_h_e
(_3,_4,_5)7 _a_r_r  (_1,_2) _d_e_l_o_c_a_l_i_z_a_t_i_o_n_s.

_0 _F_o_r _a_d_d_i_t_i_o_n_a_l _e_x_a_m_p_l_e_s _o_f $_D_E_L _i_n_p_u_t, _s_e_e _S_e_c_t_i_o_n _B._6._1_0.
#_I_B._5._3 _I_n_p_u_t _f_o_r _U_H_F _A_n_a_l_y_s_i_s#_N

_0 _D_e_l_e_t_i_o_n_s _o_f _t_h_e _a_l_p_h_a _a_n_d _b_e_t_a _F_o_c_k _m_a_t_r_i_c_e_s _c_a_n _b_e  _d_o_n_e
_i_n_d_e_p_e_n_d_e_n_t_l_y.   _T_h_e  _d_e_l_e_t_i_o_n_s  _a_r_e _i_n_p_u_t _a_s _a_b_o_v_e (_S_e_c_t_i_o_n
_B._5._2) _f_o_r _R_H_F _c_l_o_s_e_d _s_h_e_l_l,  _b_u_t  _t_h_e_y  _m_u_s_t  _b_e  _s_p_e_c_i_f_i_e_d
_s_e_p_a_r_a_t_e_l_y _f_o_r _a_l_p_h_a _a_n_d _b_e_t_a _i_n _t_h_e _U_H_F _c_a_s_e.

_0 _T_h_e _d_e_l_e_t_i_o_n _t_o _b_e _d_o_n_e _o_n _t_h_e _a_l_p_h_a _F_o_c_k _m_a_t_r_i_x  _m_u_s_t  _b_e
_p_r_e_c_e_d_e_d  _b_y  _t_h_e _k_e_y_w_o_r_d ``_A_L_P_H_A'', _a_n_d _t_h_e _d_e_l_e_t_i_o_n _o_f _t_h_e
_b_e_t_a _F_o_c_k _m_a_t_r_i_x _m_u_s_t _b_e _p_r_e_c_e_d_e_d _b_y _t_h_e  _k_e_y_w_o_r_d  ``_B_E_T_A''.
(_A_c_t_u_a_l_l_y,  _o_n_l_y _t_h_e _f_i_r_s_t _l_e_t_t_e_r ``_A'' _o_r ``_B'' _i_s _s_e_a_r_c_h_e_d
_f_o_r _b_y _t_h_e _p_r_o_g_r_a_m.)  _T_h_e _A_L_P_H_A _d_e_l_e_t_i_o_n  _m_u_s_t  _p_r_e_c_e_d_e  _t_h_e
_B_E_T_A  _d_e_l_e_t_i_o_n.   _T_h_e  _B_E_T_A  _d_e_l_e_t_i_o_n _m_a_y _b_e _t_h_e _s_a_m_e _a_s _t_h_e
_A_L_P_H_A _d_e_l_e_t_i_o_n, _o_r _d_i_f_f_e_r_e_n_t.

_0 _N_O_T_E:  _T_h_e _t_y_p_e_s _o_f _t_h_e _l_p_h_a  _N_B_O_s _o_f_t_e_n _d_i_f_f_e_r _f_r_o_m _t_h_o_s_e
_o_f  _t_h_e77777777777777777777777 t99a999999  _d77_t_i_o_n_s _l_i_s_t_s _a_r_e _g_e_n_e_r_a_l_l_y _r_e_q_u_i_r_e_d.  _F_o_r _e_x_a_m_p_l_e,
_O#_d_2#_u (_t_r_i_p_l_e_t) _h_a_s _o_n_e _b_o_n_d _i_n _t_h_e _l_p_h_a  _s_y_s_t_e_m _a_n_d  _t_h_r_e_e
_i_n _t_h_e7778 t99a999999  s99y99s99_t7778_m, _i_f _t_h_e _u_n_p_a_i_r_e_d _e_l_e_c_t_r_o_n_s _a_r_e _i_n _t_h_e _l_p_h_a  _s_y_s_-
_t_e_m.

_0 _H_e_r_e _a_r_e _t_h_r_e_e _e_x_a_m_p_l_e_s _t_o _i_l_l_u_s_t_r_a_t_e _U_H_F _o_p_e_n-_s_h_e_l_l _d_e_l_e_-
_t_i_o_n_s:

_E_x_a_m_p_l_e _1:



                       July 11, 1995





                           - 46 -


#_T
     _A_L_P_H_A  _Z_E_R_O  _1  _D_E_L_O_C  _F_R_O_M  _1  _T_O  _2
     _B_E_T_A   _N_O_S_T_A_R

#_N_E_x_a_m_p_l_e _2:
 #_T
     _A_L_P_H_A  _Z_E_R_O  _1  _D_E_L_O_C  _F_R_O_M  _1  _T_O  _2
     _B_E_T_A   _Z_E_R_O  _0  _D_E_L_O_C

#_N_E_x_a_m_p_l_e _3:
 #_T
     _A_L_P_H_A  _D_E_L_E_T_E  _0  _O_R_B_I_T_A_L_S
     _B_E_T_A   _D_E_L_E_T_E  _1  _O_R_B_I_T_A_L  _8

#_N_I_f _n_o _d_e_l_e_t_i_o_n _i_s _d_o_n_e, _t_h_i_s _m_u_s_t _b_e _s_p_e_c_i_f_i_e_d _u_s_i_n_g  _z_e_r_o
(_0)  _w_i_t_h  _o_n_e  _o_f  _t_h_e  _d_e_l_e_t_i_o_n _i_n_p_u_t _f_o_r_m_a_t_s, _a_s _s_h_o_w_n _i_n
_E_x_a_m_p_l_e_s _2,_3 _a_b_o_v_e.  #_B_B._6 _N_B_O _K_E_Y_L_I_S_T _I_L_L_U_S_T_R_A_T_I_O_N_S#_N


#_I_B._6._1 _I_n_t_r_o_d_u_c_t_i_o_n#_N

_0 _T_h_i_s _s_e_c_t_i_o_n _i_l_l_u_s_t_r_a_t_e_s _t_h_e _o_u_t_p_u_t  _p_r_o_d_u_c_e_d  _b_y  _s_e_v_e_r_a_l
_i_m_p_o_r_t_a_n_t   _k_e_y_w_o_r_d  _o_p_t_i_o_n_s  _o_f  _t_h_e  _N_B_O  _k_e_y_l_i_s_t_s  ($_N_B_O,
$_C_H_O_O_S_E, $_D_E_L, $_C_O_R_E _l_i_s_t_s), _s_u_p_p_l_e_m_e_n_t_i_n_g _t_h_e _i_l_l_u_s_t_r_a_t_i_o_n_s
_o_f _S_e_c_t_i_o_n _A._3.  _E_x_c_e_r_p_t_s _a_r_e _p_r_o_v_i_d_e_d _r_a_t_h_e_r _t_h_a_n _f_u_l_l _o_u_t_-
_p_u_t, _s_i_n_c_e, _e._g., _N_P_A _a_n_a_l_y_s_i_s  _i_s  _u_n_a_f_f_e_c_t_e_d  _b_y  _k_e_y_w_o_r_d_s
_t_h_a_t _m_o_d_i_f_y _t_h_e _N_B_O _s_e_a_r_c_h.  _K_e_y_w_o_r_d_s _o_f _g_e_n_e_r_a_l _a_p_p_l_i_c_a_b_i_l_-
_i_t_y _a_r_e _i_l_l_u_s_t_r_a_t_e_d _w_i_t_h _t_h_e _m_e_t_h_y_l_a_m_i_n_e _e_x_a_m_p_l_e (_R_H_F/_3-_2_1_G,
_P_o_p_l_e-_G_o_r_d_o_n  _g_e_o_m_e_t_r_y) _o_f _S_e_c_t_i_o_n _A._3, _w_h_i_c_h _s_h_o_u_l_d _b_e _c_o_n_-
_s_u_l_t_e_d _f_o_r _f_u_r_t_h_e_r _i_n_f_o_r_m_a_t_i_o_n.  _M_o_r_e  _s_p_e_c_i_a_l_i_z_e_d  _k_e_y_w_o_r_d_s
(_R_E_S_O_N_A_N_C_E,  _3_C_B_O_N_D,  _e_t_c.)  _a_r_e  _i_l_l_u_s_t_r_a_t_e_d _w_i_t_h _p_r_o_t_o_t_y_p_e
_m_o_l_e_c_u_l_e_s (_b_e_n_z_e_n_e, _d_i_b_o_r_a_n_e, _e_t_c.) _c_h_o_s_e_n _f_o_r _t_h_e _k_e_y_w_o_r_d.

_0 _S_e_c_t_i_o_n_s _B._6._2-_B._6._8  _i_l_l_u_s_t_r_a_t_e  _r_e_p_r_e_s_e_n_t_a_t_i_v_e  _e_x_a_m_p_l_e_s
_f_r_o_m  _t_h_e  $_N_B_O  _k_e_y_w_o_r_d  _g_r_o_u_p_s,  _i_n_c_l_u_d_i_n_g  _N_L_M_O,  _D_I_P_O_L_E,
_B_N_D_I_D_X, _R_E_S_O_N_A_N_C_E, _N_O_B_O_N_D, _3_C_B_O_N_D, _a_n_d  _m_a_t_r_i_x  _o_u_t_p_u_t  _k_e_y_-
_w_o_r_d_s.   _S_e_c_t_i_o_n  _B._6._9  _a_n_d _B._6._1_0 _s_i_m_i_l_a_r_l_y _i_l_l_u_s_t_r_a_t_e _t_h_e
_u_s_e _o_f _t_h_e $_C_H_O_O_S_E _a_n_d $_D_E_L _k_e_y_l_i_s_t_s.  _S_e_c_t_i_o_n _B._6._1_1 _i_l_l_u_s_-
_t_r_a_t_e_s  _t_h_e  _o_u_t_p_u_t  _f_o_r  _o_p_e_n-_s_h_e_l_l  _U_H_F _c_a_s_e_s, _e_m_p_h_a_s_i_z_i_n_g
_f_e_a_t_u_r_e_s _a_s_s_o_c_i_a_t_e_d _w_i_t_h _t_h_e  ``_d_i_f_f_e_r_e_n_t  _L_e_w_i_s  _s_t_r_u_c_t_u_r_e_s
_f_o_r  _d_i_f_f_e_r_e_n_t  _s_p_i_n_s''  _r_e_p_r_e_s_e_n_t_a_t_i_o_n  _o_f  _l_p_h_a   _a_n_d77777777778 t99a999999  s99p99i99n9999 m99a99n99i99f99o99l99d99s99.



_S77777777778_c_t_i_o_n _B._6._1_2 _s_h_o_w_s  _t_h_e  _e_f_f_e_c_t  _o_f  _u_s_i_n_g  _e_f_f_e_c_t_i_v_e  _c_o_r_e
_p_o_t_e_n_t_i_a_l_s  _f_o_r  _C_u#_d_2#_u,  _a_l_s_o  _i_l_l_u_s_t_r_a_t_i_n_g _a_s_p_e_c_t_s _o_f _t_h_e
_i_n_c_l_u_s_i_o_n _o_f #_I_d#_N _f_u_n_c_t_i_o_n_s.  #_I_B._6._2 _N_L_M_O _K_e_y_w_o_r_d#_N

_0 _W_h_e_n _t_h_e _N_L_M_O _k_e_y_w_o_r_d _i_s _a_c_t_i_v_a_t_e_d, _t_h_e  _p_r_o_g_r_a_m  _c_o_m_p_u_t_e_s
_t_h_e  _N_L_M_O_s  _a_n_d  _p_r_i_n_t_s  _o_u_t  _t_h_r_e_e _t_a_b_l_e_s _s_u_m_m_a_r_i_z_i_n_g _t_h_e_i_r
_f_o_r_m.  _F_o_r _t_h_e _R_H_F/_3-_2_1_G _m_e_t_h_y_l_a_m_i_n_e  _e_x_a_m_p_l_e  (_c_f.  _S_e_c_t_i_o_n
_A._3), _t_h_e _p_r_i_n_c_i_p_a_l _N_L_M_O _t_a_b_l_e _i_s _s_h_o_w_n _b_e_l_o_w:
_N_A_T_U_R_A_L _L_O_C_A_L_I_Z_E_D _M_O_L_E_C_U_L_A_R _O_R_B_I_T_A_L (_N_L_M_O) _A_N_A_L_Y_S_I_S:

_M_a_x_i_m_u_m _o_f_f-_d_i_a_g_o_n_a_l _e_l_e_m_e_n_t _o_f _D_M _i_n _N_L_M_O _b_a_s_i_s:   _0._0_0_0_0_0

_H_y_b_r_i_d_i_z_a_t_i_o_n/_P_o_l_a_r_i_z_a_t_i_o_n _A_n_a_l_y_s_i_s _o_f _N_L_M_O_s _i_n  _N_A_O  _B_a_s_i_s:



                       July 11, 1995





                           - 47 -


_N_L_M_O/_O_c_c_u_p_a_n_c_y/_P_e_r_c_e_n_t
_f_r_o_m _P_a_r_e_n_t  _N_B_O/  _A_t_o_m_i_c  _H_y_b_r_i_d  _C_o_n_t_r_i_b_u_t_i_o_n_s  ----------
---------------------------------------------------------------------
  _1. (_2._0_0_0_0_0)  _9_9._9_2_9_0%  _B_D ( _1) _C _1- _N _2
                          _4_0._0_3_9%  _C  _1  _s(  _2_1._5_4%)_p  _3._6_4(
_7_8._4_6%)
                          _5_9._8_9_1%  _N  _2  _s(  _3_0._9_8%)_p  _2._2_3(
_6_9._0_2%)
                           _0._0_1_5%  _H _3 _s(_1_0_0._0_0%)
                           _0._0_2_1%  _H _6 _s(_1_0_0._0_0%)
                           _0._0_2_1%  _H _7 _s(_1_0_0._0_0%)
  _2. (_2._0_0_0_0_0)  _9_9._9_3_0_1%  _B_D ( _1) _C _1- _H _3
                          _5_9._6_7_5%  _C  _1  _s(  _2_5._4_4%)_p  _2._9_3(
_7_4._5_6%)
                           _0._0_4_0%   _N  _2  _s(   _1._9_9%)_p_4_9._2_2(
_9_8._0_1%)
                          _4_0._2_5_8%  _H _3 _s(_1_0_0._0_0%)
  _3. (_2._0_0_0_0_0)  _9_9._6_9_9_6%  _B_D ( _1) _C _1- _H _4
                          _6_0._8_4_8%  _C  _1  _s(  _2_5._2_5%)_p  _2._9_6(
_7_4._7_5%)
                           _0._0_9_3%  _N  _2  _s(  _1_3._0_8%)_p  _6._6_5(
_8_6._9_2%)
                           _0._0_1_4%  _H _3 _s(_1_0_0._0_0%)
                          _3_8._8_6_1%  _H _4 _s(_1_0_0._0_0%)
                           _0._0_1_7%  _H _5 _s(_1_0_0._0_0%)
                           _0._1_5_8%  _H _6 _s(_1_0_0._0_0%)
  _4. (_2._0_0_0_0_0)  _9_9._6_9_9_6%  _B_D ( _1) _C _1- _H _5
                          _6_0._8_4_8%  _C  _1  _s(  _2_5._2_5%)_p  _2._9_6(
_7_4._7_5%)
                           _0._0_9_3%  _N  _2  _s(  _1_3._0_8%)_p  _6._6_5(
_8_6._9_2%)
                           _0._0_1_4%  _H _3 _s(_1_0_0._0_0%)
                           _0._0_1_7%  _H _4 _s(_1_0_0._0_0%)
                          _3_8._8_6_1%  _H _5 _s(_1_0_0._0_0%)
                           _0._1_5_8%  _H _7 _s(_1_0_0._0_0%)
  _5. (_2._0_0_0_0_0)  _9_9._7_2_0_6%  _B_D ( _1) _N _2- _H _6
                           _0._1_1_3%   _C  _1  _s(   _5._1_5%)_p_1_8._4_1(
_9_4._8_5%)
                          _6_7._9_2_9%  _N  _2  _s(  _2_5._8_2%)_p  _2._8_7(
_7_4._1_8%)
                           _0._1_3_7%  _H _4 _s(_1_0_0._0_0%)
                           _0._0_1_4%  _H _5 _s(_1_0_0._0_0%)
                          _3_1._7_9_3%  _H _6 _s(_1_0_0._0_0%)
  _6. (_2._0_0_0_0_0)  _9_9._7_2_0_6%  _B_D ( _1) _N _2- _H _7
                           _0._1_1_3%   _C  _1  _s(   _5._1_5%)_p_1_8._4_1(
_9_4._8_5%)
                          _6_7._9_2_9%  _N  _2  _s(  _2_5._8_2%)_p  _2._8_7(
_7_4._1_8%)
                           _0._0_1_4%  _H _4 _s(_1_0_0._0_0%)
                           _0._1_3_7%  _H _5 _s(_1_0_0._0_0%)
                          _3_1._7_9_3%  _H _7 _s(_1_0_0._0_0%)
  _7. (_2._0_0_0_0_0)  _9_9._9_4_9_9%  _C_R ( _1) _C _1
                          _9_9._9_5_1%   _C  _1  _s(_1_0_0._0_0%)_p  _0._0_0(
_0._0_0%)



                       July 11, 1995





                           - 48 -


_0._0_1_3%  _H _3 _s(_1_0_0._0_0%)
                           _0._0_1_3%  _H _4 _s(_1_0_0._0_0%)
                           _0._0_1_3%  _H _5 _s(_1_0_0._0_0%)
  _8. (_2._0_0_0_0_0)  _9_9._9_7_6_3%  _C_R ( _1) _N _2
                           _0._0_1_0%  _C  _1  _s(  _2_2._3_0%)_p  _3._4_8(
_7_7._7_0%)
                          _9_9._9_8_0%   _N  _2  _s(_1_0_0._0_0%)_p  _0._0_0(
_0._0_0%)
  _9. (_2._0_0_0_0_0)  _9_8._8_9_7_2%  _L_P ( _1) _N _2
                           _0._4_4_0%   _C  _1  _s(   _1._0_5%)_p_9_4._1_5(
_9_8._9_5%)
                          _9_8._8_9_7%  _N  _2  _s(  _1_7._8_5%)_p  _4._6_0(
_8_2._1_5%)
                           _0._4_8_9%  _H _3 _s(_1_0_0._0_0%)
                           _0._0_8_5%  _H _4 _s(_1_0_0._0_0%)
                           _0._0_8_5%  _H _5 _s(_1_0_0._0_0%)

 #_T

@_s_e_g



#_N_F_o_r _e_a_c_h _o_f _t_h_e _n_i_n_e  _o_c_c_u_p_l_i_e_d  _N_L_M_O_s,  _t_h_e  _t_a_b_l_e  _s_h_o_w_s
_f_i_r_s_t  _t_h_e  _N_L_M_O _o_c_c_u_p_a_n_c_y (_n_e_c_e_s_s_a_r_i_l_y _2._0_0_0_0 _a_t _S_C_F _l_e_v_e_l,
_a_s _i_n _t_h_e _p_r_e_s_e_n_t _e_x_a_m_p_l_e), _t_h_e _p_e_r_c_e_n_t_a_g_e _o_f _t_h_e _t_o_t_a_l _N_L_M_O
_c_o_m_p_o_s_i_t_i_o_n  _r_e_p_r_e_s_e_n_t_e_d _b_y _t_h_i_s _p_a_r_e_n_t _N_B_O (_u_s_u_a_l_l_y > _9_9%),
_a_n_d _t_h_e _l_a_b_e_l _o_f _t_h_e `_p_a_r_e_n_t' _N_B_O.  _B_e_l_o_w _t_h_i_s,  _t_h_e_r_e  _f_o_l_-
_l_o_w_s  _a_n  _N_A_O _d_e_c_o_m_p_o_s_i_t_i_o_n _o_f _t_h_e _N_L_M_O, _s_h_o_w_i_n_g _t_h_e _p_e_r_c_e_n_-
_t_a_g_e _o_f _t_h_e _N_L_M_O _o_n _e_a_c_h _a_t_o_m  _a_n_d  _t_h_e  _h_y_b_r_i_d  _c_o_m_p_o_s_i_t_i_o_n
_r_a_t_i_o_s  (_e_f_f_e_c_t_i_v_e #_I_s_p#_N#_u #_d _c_h_a_r_a_c_t_e_r _a_n_d _p_e_r_c_e_n_t_a_g_e #_I_s-
#_N _a_n_d #_I_p#_N-_c_h_a_r_a_c_t_e_r) _o_f _t_h_e _N_A_O_s.  _F_o_r _e_x_a_m_p_l_e, _N_L_M_O _9 _i_s
_t_h_e  _m_o_s_t _d_e_l_o_c_a_l_i_z_e_d _N_L_M_O _o_f _t_h_e _t_a_b_l_e, _h_a_v_i_n_g _o_n_l_y _a_b_o_u_t _a
_9_8._9% _c_o_n_t_r_i_b_u_t_i_o_n _f_r_o_m _t_h_e _l_o_c_a_l_i_z_e_d _N(_2) _p_a_r_e_n_t _l_o_n_e  _p_a_i_r
_N_B_O,  _w_i_t_h `_d_e_l_o_c_a_l_i_z_a_t_i_o_n _t_a_i_l_s' _c_o_m_p_o_s_e_d _p_r_i_m_a_r_i_l_y _o_f _c_o_n_-
_t_r_i_b_u_t_i_o_n_s (~_0._4% _e_a_c_h) _f_r_o_m _C(_1) _a_n_d _H(_3), _a_n_d _s_m_a_l_l_e_r _c_o_n_-
_t_r_i_b_u_t_i_o_n_s (~_0._0_9%) _f_r_o_m _H(_4) _a_n_d _H(_5).  _T_h_i_s _c_o_r_r_e_s_p_o_n_d_s _t_o
_w_h_a_t _m_i_g_h_t _h_a_v_e _b_e_e_n _a_n_t_i_c_i_p_a_t_e_d _f_r_o_m _t_h_e _N_B_O _s_u_m_m_a_r_y  _t_a_b_l_e
(_S_e_c_t_i_o_n _A._3._6) _o_r _p_e_r_t_u_r_b_a_t_i_o_n _t_h_e_o_r_y _e_n_e_r_g_y _a_n_a_l_y_s_i_s _t_a_b_l_e
(_S_e_c_t_i_o_n _A._3._5), _w_h_i_c_h _s_h_o_w_e_d _t_h_a_t _t_h_e _N(_2) _l_o_n_e  _p_a_i_r,  _N_B_O
_9,  _i_s  _p_r_i_n_c_i_p_a_l_l_y  _d_e_l_o_c_a_l_i_z_e_d  _o_n_t_o  _N_B_O  _2_4, _t_h_e _v_i_c_i_n_a_l
_C(_1)-_H(_3) _a_n_t_i_b_o_n_d [_w_i_t_h _l_e_s_s_e_r  _d_e_l_o_c_a_l_i_z_a_t_i_o_n_s  _o_n_t_o  _N_B_O_s
_2_5,  _2_6,  _t_h_e  _C(_1)-_H(_4)  _a_n_d _C(_1)-_H(_5) _a_n_t_i_b_o_n_d_s].  #_I_B._6._3
_D_I_P_O_L_E _K_e_y_w_o_r_d#_N

_0 _T_h_e _D_I_P_O_L_E _k_e_y_w_o_r_d _a_c_t_i_v_a_t_e_s _t_h_e _N_B_O/_N_L_M_O _a_n_a_l_y_s_i_s _o_f  _t_h_e
_m_o_l_e_c_u_l_a_r  _d_i_p_o_l_e  _m_o_m_e_n_t, _a_s _s_h_o_w_n _b_e_l_o_w _f_o_r _t_h_e _e_x_a_m_p_l_e _o_f
_R_H_F/_3-_2_1_G _m_e_t_h_y_l_a_m_i_n_e (_c_f. _S_e_c_t_i_o_n _A._3):
_D_i_p_o_l_e _m_o_m_e_n_t _a_n_a_l_y_s_i_s:

[_P_r_i_n_t _t_h_r_e_s_h_o_l_d: _N_e_t _d_i_p_o_l_e > _0._0_2 _D_e_b_y_e]

                                _N_L_M_O       _b_o_n_d       _d_i_p_o_l_e
_N_B_O _b_o_n_d _d_i_p_o_l_e



                       July 11, 1995





                           - 49 -


-------------------------  ------------------------
         _O_r_b_i_t_a_l              _x     _y     _z    _T_o_t_a_l       _x
_y                            _z                         _T_o_t_a_l
===============================================================================
  _1. _B_D ( _1) _C _1- _N _2       -_0._7_6 -_0._0_8  _0._0_0  _0._7_6    -_0._7_6
-_0._0_9  _0._0_0  _0._7_7

  _2. _B_D ( _1) _C _1- _H _3        _0._4_9  _1._9_0  _0._0_0  _1._9_6     _0._5_0
_1._9_0  _0._0_0  _1._9_7
                                            _d_e_l_o_c  _1_4:  _0._0_3
-_0._0_1  _0._0_0  _0._0_3
                                            _d_e_l_o_c  _2_5: -_0._0_1
_0._0_0  _0._0_2  _0._0_2
                                            _d_e_l_o_c  _2_6: -_0._0_1
_0._0_0 -_0._0_2  _0._0_2

  _3. _B_D ( _1) _C _1- _H _4        _0._6_7 -_0._7_7 -_1._5_0  _1._8_1     _0._7_1
-_0._7_9 -_1._5_0  _1._8_4
                                            _d_e_l_o_c  _2_7: -_0._0_5
_0._0_0  _0._0_0  _0._0_5
                                            _d_e_l_o_c  _2_6: -_0._0_2
_0._0_3 -_0._0_3  _0._0_4
                                            _d_e_l_o_c  _2_4: -_0._0_1
-_0._0_2  _0._0_0  _0._0_2

  _4. _B_D ( _1) _C _1- _H _5        _0._6_7 -_0._7_7  _1._5_0  _1._8_1     _0._7_1
-_0._7_9  _1._5_0  _1._8_4
                                            _d_e_l_o_c  _2_8: -_0._0_5
_0._0_0  _0._0_0  _0._0_5
                                            _d_e_l_o_c  _2_5: -_0._0_2
_0._0_3  _0._0_3  _0._0_4
                                            _d_e_l_o_c  _2_4: -_0._0_1
-_0._0_2  _0._0_0  _0._0_2

  _5. _B_D ( _1) _N _2- _H _6       -_0._4_5  _0._4_4  _0._8_6  _1._0_6    -_0._5_0
_0._4_4  _0._8_9  _1._1_1
                                            _d_e_l_o_c  _2_5:  _0._0_6
-_0._0_1 -_0._0_2  _0._0_6

  _6. _B_D ( _1) _N _2- _H _7       -_0._4_5  _0._4_4 -_0._8_6  _1._0_6    -_0._5_0
_0._4_4 -_0._8_9  _1._1_1
                                            _d_e_l_o_c  _2_6:  _0._0_6
-_0._0_1  _0._0_2  _0._0_6

  _7. _C_R ( _1) _C _1             _0._0_0  _0._0_0  _0._0_0  _0._0_0     _0._0_0
_0._0_0  _0._0_0  _0._0_0

  _8. _C_R ( _1) _N _2             _0._0_0  _0._0_1  _0._0_0  _0._0_1     _0._0_0
_0._0_0  _0._0_0  _0._0_0

  _9. _L_P ( _1) _N _2            -_0._6_3 -_2._8_5  _0._0_0  _2._9_1    -_0._8_8
-_2._9_3  _0._0_0  _3._0_6
                                            _d_e_l_o_c  _2_4:  _0._1_6
_0._0_9  _0._0_0  _0._1_8



                       July 11, 1995





                           - 50 -


_d_e_l_o_c  _2_5:  _0._0_3  _0._0_1  _0._0_1  _0._0_3
                                            _d_e_l_o_c  _2_6:  _0._0_3
_0._0_1 -_0._0_1  _0._0_3
                                            _d_e_l_o_c  _1_0:  _0._0_2
-_0._0_2  _0._0_0  _0._0_3
                           ----------
------------------------------------------
        _N_e_t _d_i_p_o_l_e _m_o_m_e_n_t   -_0._4_5 -_1._6_7  _0._0_0  _1._7_3    -_0._7_1
-_1._8_2       _0._0_0      _1._9_5     _D_e_l_o_c_a_l_i_z_a_t_i_o_n     _c_o_r_r_e_c_t_i_o_n
_0._2_7  _0._1_4  _0._0_0  _0._3_0
                           ----------
------------------------------------------
      _T_o_t_a_l _d_i_p_o_l_e _m_o_m_e_n_t   -_0._4_5 -_1._6_7  _0._0_0  _1._7_3    -_0._4_5
-_1._6_7  _0._0_0  _1._7_3

 #_T

@_s_e_g



#_N_T_h_e _b_o_t_t_o_m _l_i_n_e _o_f _t_h_e _t_a_b_l_e _s_h_o_w_s _t_h_e _i_n_d_i_v_i_d_u_a_l  (_x,_y,_z)
_v_e_c_t_o_r  _c_o_m_p_o_n_e_n_t_s  (_m_i_n_u_s  _0._4_5,_m_i_n_u_s _1._6_7,_0._0_0) _a_n_d _l_e_n_g_t_h
(_1._7_3 _D) _o_f _t_h_e _t_o_t_a_l _m_o_l_e_c_u_l_a_r _d_i_p_o_l_e _m_o_m_e_n_t, _i_n _t_h_e  _c_o_o_r_-
_d_i_n_a_t_e _s_y_s_t_e_m _o_f _t_h_e _E_S_S _p_r_o_g_r_a_m.  _T_h_i_s _i_s _d_e_c_o_m_p_o_s_e_d _i_n _t_h_e
_m_a_i_n _b_o_d_y _o_f _t_h_e _t_a_b_l_e _i_n_t_o _t_h_e _i_n_d_i_v_i_d_u_a_l _c_o_n_t_r_i_b_u_t_i_o_n_s  _o_f
``_N_L_M_O  _b_o_n_d  _d_i_p_o_l_e_s''  (_w_h_i_c_h _s_t_r_i_c_t_l_y _a_d_d _t_o _g_i_v_e _t_h_e _n_e_t
_m_o_l_e_c_u_l_e _d_i_p_o_l_e _a_t _t_h_e _S_C_F _l_e_v_e_l) _a_n_d ``_N_B_O  _b_o_n_d  _d_i_p_o_l_e_s''
(_w_h_i_c_h _m_u_s_t _b_e _a_d_d_e_d _w_i_t_h _t_h_e_i_r _o_f_f-_d_i_a_g_o_n_a_l `_d_e_l_o_c' _c_o_n_t_r_i_-
_b_u_t_i_o_n_s _t_o _g_i_v_e _t_h_e _n_e_t _m_o_l_e_c_u_l_a_r _m_o_m_e_n_t).  _E_a_c_h _N_L_M_O _o_r _N_B_O
_b_o_n_d _d_i_p_o_l_e _v_e_c_t_o_r _t _m_u #_d_A_B #_u _i_s _e_v_a_l_u_a_t_e_d _a_s

_m_a_b  = _m_a_b_e  + _m_a_b_n

_w_h_e_r_e _m_a_b_e  = _2#_I_e#_N77a9999 b9999 _a77 _t _r#_N_a_r _b _t _i_s _t_h_e _e_l_e_c_t_r_o_n_i_c _d_i_p_o_l_e
_e_x_p_e_c_t_a_t_i_o_n  _v_a_l_u_e  _f_o_r  _a_n  _e_l_e_c_t_r_o_n _p_a_i_r _i_n _t_h_e _b  _N_L_M_O _o_r
_N_B_O, _a_n_d _m_a_b_n  _i_s _t_h_e _n_u_c_l_e_a_r _c_o_n_t_r_i_b_u_t_i_o_n  _o_f  _c_o_m_p_e_n_s_a_t_i_n_g
_u_n_i_t _p_o_s_i_t_i_v_e _c_h_a_r_g_e_s _a_t _t_h_e _p_o_s_i_t_i_o_n_s _o_f _n_u_c_l_e_i _A _a_n_d _B (_o_r
_b_o_t_h _o_n _A _f_o_r _a _1-_c_e_n_t_e_r _N_B_O).   _T_h_e  `_d_e_l_o_c'  _c_o_n_t_r_i_b_u_t_i_o_n_s
_b_e_l_o_w _e_a_c_h _N_B_O _b_o_n_d _d_i_p_o_l_e _s_h_o_w _t_h_e _o_f_f-_d_i_a_g_o_n_a_l _c_o_r_r_e_c_t_i_o_n_s
_t_o _a_n _a_d_d_i_t_i_v_e _b_o_n_d _d_i_p_o_l_e _a_p_p_r_o_x_i_m_a_t_i_o_n (_i._e., _t_h_e  _c_o_r_r_e_c_-
_t_i_o_n_s  _t_o  _l_o_c_a_l_i_z_e_d  _N_B_O  _b_o_n_d _d_i_p_o_l_e_s _t_o _g_e_t _t_h_e _N_L_M_O _b_o_n_d
_d_i_p_o_l_e_s) _t_o _a_c_c_o_u_n_t _f_o_r _t_h_e _d_e_l_o_c_a_l_i_z_a_t_i_o_n _f_r_o_m  _p_a_r_e_n_t  _N_B_O
#_I_i#_N _o_n_t_o _o_t_h_e_r (_p_r_i_m_a_r_i_l_y, _n_o_n-_L_e_w_i_s) _N_B_O_s #_I_j#_N; _i_n _t_e_r_m_s
_o_f _t_h_e _e_x_p_a_n_s_i_o_n _o_f _a_n _N_L_M_O _i_n _t_h_e _s_e_t { } _o_f _N_B_O_s,

_n_l_m_o  =  _t_h_i_s _c_o_r_r_e_c_t_i_o_n _i_s (_f_o_r _e_a_c_h _e_l_e_c_t_r_o_n, _l_p_h_a  _o_r7777 t99a



s
p
i
n
)7777._L_M+_1_0

+ _s <<_k>> _w_h_e_r_e _t_h_e _p_r_i_m_e_s _o_n _t_h_e _s_u_m_m_a_t_i_o_n _d_e_n_o_t_e  _o_m_i_s_s_i_o_n
_o_f _t_e_r_m_s #_I_k#_N _e_q_u_a_l _t_o #_I_i#_N _o_r #_I_j#_N.  _F_o_r _e_x_a_m_p_l_e, _i_n _t_h_e
_a_b_o_v_e _t_a_b_l_e _t_h_e _l_a_r_g_e_s_t _i_n_d_i_v_i_d_u_a_l _c_o_n_t_r_i_b_u_t_i_o_n _t_o _t _m_u   _i_s
_f_r_o_m  _t_h_e  _n_i_t_r_o_g_e_n  _l_o_n_e  _p_a_i_r, _t_a_b_l_e _e_n_t_r_y _9, _w_h_i_c_h _h_a_s _a_n
_N_L_M_O _d_i_p_o_l_e _o_f _2._9_1 _D_e_b_y_e _o_r _N_B_O _d_i_p_o_l_e _o_f _3._0_6.  _T_h_e _l_a_t_t_e_r



                       July 11, 1995





                           - 51 -


_h_a_s
_a_l_s_o _t_h_e _l_a_r_g_e_s_t _o_f_f-_d_i_a_g_o_n_a_l _d_e_l_o_c_a_l_i_z_a_t_i_o_n  _c_o_r_r_e_c_t_i_o_n  _i_n
_t_h_e  _t_a_b_l_e,  _a  _0._1_8  _D _c_o_r_r_e_c_t_i_o_n _d_u_e _t_o _t_h_e #_I_n#_N#_d_N#_u7 _a_r_r
_g_m_a *#<#_d_C_H#_u  _d_e_l_o_c_a_l_i_z_a_t_i_o_n  _i_n_t_o  _t_h_e  _v_i_c_i_n_a_l  _C(_1)-_H(_3)
_a_n_t_i_b_o_n_d, _N_B_O _2_4.

_0 _F_o_r _a _p_o_s_t-_S_C_F (_c_o_r_r_e_l_a_t_e_d) _c_a_l_c_u_l_a_t_i_o_n, _t_h_e _d_i_p_o_l_e  _t_a_b_l_e
_w_o_u_l_d _a_l_s_o _i_n_c_l_u_d_e _a_n _a_d_d_i_t_i_o_n_a_l _l_i_n_e _f_o_r _t_h_e _c_o_r_r_e_c_t_i_o_n _d_u_e
_t_o _n_o_n-_a_d_d_i_t_i_v_i_t_y _o_f _t_h_e _N_L_M_O _b_o_n_d _d_i_p_o_l_e_s.   _F_o_r  _a_n  _i_o_n_i_c
_s_p_e_c_i_e_s,  _t_h_e_r_e  _w_o_u_l_d  _a_l_s_o  _b_e  _a_n _a_d_d_i_t_i_o_n_a_l _l_i_n_e _f_o_r _t_h_e
``_r_e_s_i_d_u_a_l _n_u_c_l_e_a_r _c_h_a_r_g_e'' _c_o_n_t_r_i_b_u_t_i_o_n; _h_e_r_e, _o_n_e _m_u_s_t  _b_e
_a_w_a_r_e  _t_h_a_t  _t_h_e _d_i_p_o_l_e _m_o_m_e_n_t _i_s _c_a_l_c_u_l_a_t_e_d _w_i_t_h _r_e_s_p_e_c_t _t_o
_t_h_e _o_r_i_g_i_n _o_f _t_h_e _c_a_r_t_e_s_i_a_n _c_o_o_r_d_i_n_a_t_e _s_y_s_t_e_m _c_h_o_s_e_n _b_y  _t_h_e
_E_S_S  _p_r_o_g_r_a_m (_s_i_n_c_e _t_h_e _d_i_p_o_l_e _m_o_m_e_n_t _i_s _o_r_i_g_i_n-_d_e_p_e_n_d_e_n_t _i_n
_t_h_i_s _c_a_s_e).

_0 _N_o_t_e _t_h_a_t _t_h_e _a_m_o_u_n_t _o_f _d_e_t_a_i_l _i_n _t_h_e _d_i_p_o_l_e _t_a_b_l_e _c_a_n  _b_e
_a_l_t_e_r_e_d  _b_y  _u_s_i_n_g _t_h_e ``_D_I_P_O_L_E=_t_h_r'' _f_o_r_m _o_f _t_h_e _k_e_y_w_o_r_d _t_o
_a_l_t_e_r _t_h_e _t_h_r_e_s_h_o_l_d _d_i_p_o_l_e (`_t_h_r')  _f_o_r  _p_r_i_n_t_i_n_g  [_d_e_f_a_u_l_t:
_0._0_2 _D].  #_I_B._6._4 _M_a_t_r_i_x _O_u_t_p_u_t _K_e_y_w_o_r_d_s#_N

_0 _T_w_o _s_i_m_p_l_e _e_x_a_m_p_l_e_s _w_i_l_l _b_e _g_i_v_e_n _t_o _i_l_l_u_s_t_r_a_t_e  _t_h_e  _f_o_r_-
_m_a_t_t_i_n_g  _o_f _o_u_t_p_u_t _f_o_r _o_p_e_r_a_t_o_r_s _o_r _b_a_s_i_s _s_e_t _t_r_a_n_s_f_o_r_m_a_t_i_o_n
_m_a_t_r_i_c_e_s _u_s_i_n_g _t_h_e _m_a_t_r_i_x _o_u_t_p_u_t _k_e_y_w_o_r_d_s _o_f _S_e_c_t_i_o_n  _B._2._4.
_F_o_r  _t_h_e  _R_H_F/_3-_2_1_G  _m_e_t_h_y_l_a_m_i_n_e _e_x_a_m_p_l_e _o_f _S_e_c_t_i_o_n _A._3, _t_h_e
_k_e_y_w_o_r_d ``_F_N_H_O'' _w_o_u_l_d _c_a_u_s_e _t_h_e  _F_o_c_k  _m_a_t_r_i_x  _i_n  _t_h_e  _N_H_O
_b_a_s_i_s  _t_o  _b_e _p_r_i_n_t_e_d _o_u_t.  _S_h_o_w_n _b_e_l_o_w _i_s _a _r_e_p_r_o_d_u_c_t_i_o_n _o_f
_t_h_e _f_i_r_s_t _e_i_g_h_t _c_o_l_u_m_n_s (_o_u_t _o_f _2_8) _o_f _t_h_i_s _o_u_t_p_u_t:
_N_H_O _F_o_c_k _m_a_t_r_i_x:

         _N_H_O         _1        _2        _3         _4         _5
_6       _7       _8
     ---------- ------- ------- ------- ------- -------  ---
---- ------- -------
  _1.  _C_1 ( _N_2 )  -_0._0_2_0_8  -_0._7_2_0_3  -_0._0_5_7_1  -_0._0_6_6_5   _0._0_4_3_8
_0._0_6_7_2  _0._0_4_3_8  _0._0_6_7_2
  _2.  _N_2 ( _C_1 )  -_0._7_2_0_3  -_0._3_0_8_3  -_0._0_7_7_3  -_0._0_6_2_7   _0._0_8_3_5
_0._0_6_4_6  _0._0_8_3_5  _0._0_6_4_6
  _3.  _C_1 ( _H_3 )  -_0._0_5_7_1  -_0._0_7_7_3  -_0._1_3_9_4  -_0._6_7_5_8   _0._0_6_3_8
_0._0_7_4_6  _0._0_6_3_8  _0._0_7_4_6
  _4.  _H_3 ( _C_1 )  -_0._0_6_6_5  -_0._0_6_2_7  -_0._6_7_5_8   _0._1_3_4_9   _0._0_7_4_0
_0._0_6_7_2  _0._0_7_4_0  _0._0_6_7_2
  _5.  _C_1 ( _H_4 )   _0._0_4_3_8   _0._0_8_3_5   _0._0_6_3_8   _0._0_7_4_0  -_0._1_4_6_6
-_0._6_7_6_1 -_0._0_5_4_8 -_0._0_7_5_9
  _6.  _H_4 ( _C_1 )   _0._0_6_7_2   _0._0_6_4_6   _0._0_7_4_6   _0._0_6_7_2  -_0._6_7_6_1
_0._1_5_4_1 -_0._0_7_5_9 -_0._0_6_9_7
  _7.  _C_1 ( _H_5 )   _0._0_4_3_8   _0._0_8_3_5   _0._0_6_3_8   _0._0_7_4_0  -_0._0_5_4_8
-_0._0_7_5_9 -_0._1_4_6_6 -_0._6_7_6_1
  _8.  _H_5 ( _C_1 )   _0._0_6_7_2   _0._0_6_4_6   _0._0_7_4_6   _0._0_6_7_2  -_0._0_7_5_9
-_0._0_6_9_7 -_0._6_7_6_1  _0._1_5_4_1
  _9.  _N_2 ( _H_6 )   _0._0_9_2_6   _0._1_4_9_9   _0._0_2_4_0  -_0._0_1_1_3   _0._0_9_1_2
-_0._0_0_7_8 -_0._0_3_4_9  _0._0_1_3_4
 _1_0.  _H_6 ( _N_2 )   _0._1_0_8_3   _0._0_8_2_6  -_0._0_0_1_0   _0._0_2_3_2  -_0._0_1_1_8
-_0._0_2_4_2  _0._0_0_1_7 -_0._0_2_2_4



                       July 11, 1995





                           - 52 -


_1_1.  _N_2 ( _H_7  )   _0._0_9_2_6   _0._1_4_9_9   _0._0_2_4_0  -_0._0_1_1_3  -_0._0_3_4_9
_0._0_1_3_4  _0._0_9_1_2 -_0._0_0_7_8
 _1_2.  _H_7 ( _N_2 )   _0._1_0_8_3   _0._0_8_2_6  -_0._0_0_1_0   _0._0_2_3_2   _0._0_0_1_7
-_0._0_2_2_4 -_0._0_1_1_8 -_0._0_2_4_2
 _1_3.  _C_1 (_c_r)     _0._3_9_6_2   _0._4_1_6_8   _0._4_4_0_0   _0._3_8_9_3  -_0._4_4_4_7
-_0._3_8_6_9 -_0._4_4_4_7 -_0._3_8_6_9
 _1_4.  _N_2 (_c_r)     _0._6_1_4_7   _0._7_0_8_3   _0._0_0_3_9   _0._0_2_4_9  -_0._0_1_3_0
-_0._0_2_5_1 -_0._0_1_3_0 -_0._0_2_5_1
 _1_5.  _N_2 (_l_p)     _0._0_7_6_2   _0._0_9_5_5  -_0._1_0_4_3   _0._0_2_5_4  -_0._0_3_8_6
_0._0_1_6_0 -_0._0_3_8_6  _0._0_1_6_0
 _1_6.  _C_1 (_r_y*)   -_0._1_3_2_0   _0._0_9_2_4   _0._0_7_0_5  -_0._0_8_1_5   _0._0_0_2_2
-_0._0_0_3_7  _0._0_0_2_2 -_0._0_0_3_7
 _1_7.  _C_1 (_r_y*)    _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0   _0._0_7_1_9
-_0._0_9_1_0 -_0._0_7_1_9  _0._0_9_1_0
 _1_8.  _C_1 (_r_y*)   -_0._1_0_2_3   _0._0_7_6_4  -_0._0_6_4_3   _0._0_7_9_5  -_0._0_0_7_4
_0._0_1_0_5 -_0._0_0_7_4  _0._0_1_0_5
 _1_9.  _C_1 (_r_y*)    _0._0_2_6_6  -_0._0_2_1_3   _0._0_0_1_9  -_0._0_0_5_7   _0._0_6_6_7
-_0._0_7_8_8  _0._0_6_6_7 -_0._0_7_8_8
 _2_0.  _N_2 (_r_y*)    _0._0_1_5_1  -_0._0_1_7_7  -_0._0_3_5_1  -_0._0_1_7_2  -_0._0_1_7_9
-_0._0_1_4_6 -_0._0_1_7_9 -_0._0_1_4_6
 _2_1.  _N_2 (_r_y*)    _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0  -_0._0_1_5_8
-_0._0_2_4_9  _0._0_1_5_8  _0._0_2_4_9
 _2_2.  _N_2 (_r_y*)    _0._1_7_9_9  -_0._1_4_4_0  -_0._0_0_6_4   _0._0_2_9_5   _0._0_0_3_8
-_0._0_2_8_9  _0._0_0_3_8 -_0._0_2_8_9
 _2_3.  _N_2 (_r_y*)    _0._0_1_8_3  -_0._0_1_3_6  -_0._0_0_5_1   _0._0_2_1_3   _0._0_0_3_2
-_0._0_0_9_5  _0._0_0_3_2 -_0._0_0_9_5
 _2_4.  _H_3 (_r_y*)    _0._0_2_5_3  -_0._0_0_3_8   _0._2_8_3_4  -_0._3_4_9_7  -_0._0_2_4_8
_0._0_0_4_7 -_0._0_2_4_8  _0._0_0_4_7
 _2_5.  _H_4 (_r_y*)    _0._0_2_2_3  -_0._0_0_7_1   _0._0_2_1_1  -_0._0_0_6_8  -_0._2_7_8_9
_0._3_5_5_3 -_0._0_2_2_7  _0._0_0_6_9
 _2_6.  _H_5 (_r_y*)    _0._0_2_2_3  -_0._0_0_7_1   _0._0_2_1_1  -_0._0_0_6_8  -_0._0_2_2_7
_0._0_0_6_9 -_0._2_7_8_9  _0._3_5_5_3
 _2_7.  _H_6 (_r_y*)    _0._0_1_2_4   _0._0_1_7_2  -_0._0_0_6_7   _0._0_2_1_9  -_0._0_0_8_0
_0._0_0_9_7  _0._0_0_5_7 -_0._0_2_2_2
 _2_8.  _H_7 (_r_y*)    _0._0_1_2_4   _0._0_1_7_2  -_0._0_0_6_7   _0._0_2_1_9   _0._0_0_5_7
-_0._0_2_2_2 -_0._0_0_8_0  _0._0_0_9_7

 #_T

@_s_e_g

 #_N

_0 _T_h_e _N_H_O _l_a_b_e_l_s _o_n _e_a_c_h _r_o_w _i_d_e_n_t_i_f_y _t_h_e _a_t_o_m _t_o _w_h_i_c_h  _t_h_e
_N_H_O  _b_e_l_o_n_g_s, _a_n_d (_i_n _p_a_r_e_n_t_h_e_s_e_s) _t_h_e _a_t_o_m _t_o_w_a_r_d _w_h_i_c_h _t_h_e
_h_y_b_r_i_d _i_s _p_o_i_n_t_e_d, _i_f _a _b_o_n_d _h_y_b_r_i_d,  _o_r  _a  _1-_c_e_n_t_e_r  _l_a_b_e_l
(_c_r,  _l_p, _l_p*, _o_r _r_y*), _i_f _a _n_o_n-_b_o_n_d_e_d _h_y_b_r_i_d.  _T_h_u_s, ``_C _1
(_N _2)'' (_N_H_O _1) _i_s  _t_h_e  _b_o_n_d_i_n_g  _h_y_b_r_i_d  _o_n  _C(_1)  _d_i_r_e_c_t_e_d
_t_o_w_a_r_d  _N(_2),  ``_N  _2(_l_p)''  (_N_B_O  _1_5) _i_s _a _n_o_n-_b_o_n_d_e_d (_l_o_n_e
_p_a_i_r) _h_y_b_r_i_d _o_n _N(_2), _e_t_c.  _T_h_i_s _l_a_b_e_l _a_l_l_o_w_s  _o_n_e  _t_o  _f_i_n_d
_t_h_e  _p_r_e_c_i_s_e  _f_o_r_m  _o_f  _t_h_e _N_H_O _i_n _t_h_e _m_a_i_n _l_i_s_t_i_n_g _o_f _N_B_O_s.
_T_h_e _F_N_H_O _m_a_t_r_i_x _s_h_o_w_s, _f_o_r  _e_x_a_m_p_l_e,  _t_h_a_t  _t_h_e  (_1,_2)  _F_o_c_k
_m_a_t_r_i_x _e_l_e_m_e_n_t _b_e_t_w_e_e_n _t_h_e _d_i_r_e_c_t_l_y _i_n_t_e_r_a_c_t_i_n_g _N_H_O_s _f_o_r_m_i_n_g
_t_h_e _C-_N _b_o_n_d _N_B_O _i_s -_0._7_2_0_3 _a._u., _w_h_e_r_e_a_s _t_h_e  (_1,_9)  _m_a_t_r_i_x



                       July 11, 1995





                           - 53 -


_e_l_e_m_e_n_t,
_b_e_t_w_e_e_n _t_h_e _C(_1) _h_y_b_r_i_d _p_o_i_n_t_i_n_g _t_o_w_a_r_d _N(_2)  _a_n_d  _t_h_e  _N(_2)
_h_y_b_r_i_d _p_o_i_n_t_i_n_g _t_o_w_a_r_d _H(_6), _i_s _0._0_9_2_6 _a._u.

_0 _A_s _a _s_e_c_o_n_d  _e_x_a_m_p_l_e,  _t_h_e  _k_e_y_w_o_r_d  ``_N_B_O_M_O=_P_V_A_L''  _w_o_u_l_d
_p_r_i_n_t  _o_u_t  _t_h_e  _c_o_r_e  +  _v_a_l_e_n_c_e _c_o_l_u_m_n_s _o_f _t_h_e _N_B_O7 _a_r_r  _M_O
_t_r_a_n_s_f_o_r_m_a_t_i_o_n, _a_s _r_e_p_r_o_d_u_c_e_d _b_e_l_o_w:
_M_O_s _i_n _t_h_e _N_B_O _b_a_s_i_s:

         _N_B_O         _1        _2        _3         _4         _5
_6       _7       _8
     ---------- ------- ------- ------- ------- -------  ---
---- ------- -------
  _1.  _C_1 - _N_2    -_0._0_6_6_1  -_0._0_5_7_4   _0._6_2_8_8  -_0._1_2_4_3   _0._0_0_0_0
-_0._3_2_3_9  _0._6_8_1_6  _0._0_0_0_0
  _2.  _C_1 - _H_3    -_0._0_0_1_8  -_0._0_5_7_8   _0._2_0_6_1  -_0._4_7_1_6   _0._0_0_0_0
_0._7_7_4_7  _0._1_3_8_6  _0._0_0_0_0
  _3.  _C_1 - _H_4     _0._0_0_2_3   _0._0_5_7_9  -_0._1_8_3_6   _0._4_9_0_8   _0._3_8_1_3
_0._2_3_0_4  _0._3_9_2_1  _0._5_9_4_0
  _4.  _C_1 - _H_5     _0._0_0_2_3   _0._0_5_7_9  -_0._1_8_3_6   _0._4_9_0_8  -_0._3_8_1_3
_0._2_3_0_4  _0._3_9_2_1 -_0._5_9_4_0
  _5.  _N_2 - _H_6     _0._0_5_7_0   _0._0_0_0_0  -_0._4_7_4_2  -_0._3_5_6_7  -_0._5_9_3_7
-_0._1_9_5_4  _0._3_0_3_5  _0._3_8_1_4
  _6.  _N_2 - _H_7     _0._0_5_7_0   _0._0_0_0_0  -_0._4_7_4_2  -_0._3_5_6_7   _0._5_9_3_7
-_0._1_9_5_4  _0._3_0_3_5 -_0._3_8_1_4
  _7.  _C_1 (_c_r)    -_0._0_0_2_1   _0._9_9_3_1   _0._0_6_9_2  -_0._0_9_2_0   _0._0_0_0_0
_0._0_0_0_6  _0._0_0_1_9  _0._0_0_0_0
  _8.  _N_2 (_c_r)     _0._9_9_3_5  -_0._0_0_1_9   _0._1_0_4_8   _0._0_3_4_8   _0._0_0_0_0
-_0._0_1_3_1  _0._0_0_2_2  _0._0_0_0_0
  _9.  _N_2 (_l_p)     _0._0_4_3_2  -_0._0_0_3_7  -_0._1_6_7_6  -_0._1_2_1_9   _0._0_0_0_0
_0._3_3_1_2  _0._1_5_2_5  _0._0_0_0_0
 _1_0.  _C_1 (_r_y*)   -_0._0_0_8_8  -_0._0_0_0_5   _0._0_1_1_4   _0._0_0_8_9   _0._0_0_0_0
-_0._0_0_1_6 -_0._0_0_8_6  _0._0_0_0_0
 _1_1.  _C_1 (_r_y*)    _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0   _0._0_1_0_9
_0._0_0_0_0  _0._0_0_0_0 -_0._0_0_7_0
 _1_2.  _C_1 (_r_y*)   -_0._0_0_6_3   _0._0_0_0_1  -_0._0_0_5_0  -_0._0_0_3_5   _0._0_0_0_0
-_0._0_0_3_0  _0._0_0_2_6  _0._0_0_0_0
 _1_3.  _C_1 (_r_y*)    _0._0_0_2_0  -_0._0_0_0_2  -_0._0_0_0_3  -_0._0_0_0_3   _0._0_0_0_0
-_0._0_0_0_9  _0._0_0_0_2  _0._0_0_0_0
 _1_4.  _N_2 (_r_y*)   -_0._0_0_4_1  -_0._0_0_0_3  -_0._0_0_0_6   _0._0_0_1_6   _0._0_0_0_0
_0._0_1_9_2  _0._0_1_0_7  _0._0_0_0_0
 _1_5.  _N_2 (_r_y*)    _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0   _0._0_0_8_0
_0._0_0_0_0  _0._0_0_0_0  _0._0_1_2_4
 _1_6.  _N_2 (_r_y*)    _0._0_0_3_5  -_0._0_0_6_0  -_0._0_0_3_9   _0._0_1_0_2   _0._0_0_0_0
-_0._0_0_2_3  _0._0_0_4_0  _0._0_0_0_0
 _1_7.  _N_2 (_r_y*)   -_0._0_0_1_8   _0._0_0_2_3  -_0._0_0_0_7   _0._0_0_1_3   _0._0_0_0_0
-_0._0_0_0_7  _0._0_0_0_5  _0._0_0_0_0
 _1_8.  _H_3 (_r_y*)   -_0._0_0_0_8  -_0._0_0_9_4  -_0._0_1_0_3   _0._0_1_4_6   _0._0_0_0_0
_0._0_0_1_7 -_0._0_0_2_1  _0._0_0_0_0
 _1_9.  _H_4 (_r_y*)   -_0._0_0_0_8  -_0._0_1_0_0  -_0._0_0_6_1   _0._0_1_1_9   _0._0_0_6_2
_0._0_0_0_4 -_0._0_0_5_4 -_0._0_0_9_8
 _2_0.  _H_5 (_r_y*)   -_0._0_0_0_8  -_0._0_1_0_0  -_0._0_0_6_1   _0._0_1_1_9  -_0._0_0_6_2
_0._0_0_0_4 -_0._0_0_5_4  _0._0_0_9_8
 _2_1.  _H_6 (_r_y*)   -_0._0_0_5_2  -_0._0_0_1_3  -_0._0_1_4_7  -_0._0_0_1_8  -_0._0_0_2_7



                       July 11, 1995





                           - 54 -


-_0._0_0_1_6
-_0._0_0_9_7 -_0._0_1_5_9
 _2_2.  _H_7 (_r_y*)   -_0._0_0_5_2  -_0._0_0_1_3  -_0._0_1_4_7  -_0._0_0_1_8   _0._0_0_2_7
-_0._0_0_1_6 -_0._0_0_9_7  _0._0_1_5_9
 _2_3.  _C_1 - _N_2 *  -_0._0_0_1_9  -_0._0_0_3_5  -_0._0_0_2_6   _0._0_0_2_5   _0._0_0_0_0
_0._0_0_4_3  _0._0_0_4_9  _0._0_0_0_0
 _2_4.  _C_1 - _H_3 *  -_0._0_0_1_3  -_0._0_0_2_4   _0._0_0_5_9  -_0._0_0_1_8   _0._0_0_0_0
-_0._0_3_4_9 -_0._0_1_3_9  _0._0_0_0_0
 _2_5.  _C_1 - _H_4 *   _0._0_0_0_9   _0._0_0_2_8  -_0._0_1_3_8   _0._0_0_3_3  -_0._0_4_0_8
-_0._0_1_8_8  _0._0_0_6_1  _0._0_1_4_8
 _2_6.  _C_1 - _H_5 *   _0._0_0_0_9   _0._0_0_2_8  -_0._0_1_3_8   _0._0_0_3_3   _0._0_4_0_8
-_0._0_1_8_8  _0._0_0_6_1 -_0._0_1_4_8
 _2_7.  _N_2 - _H_6 *  -_0._0_0_1_0   _0._0_0_5_1  -_0._0_0_4_7   _0._0_1_8_2   _0._0_1_7_9
_0._0_1_2_2  _0._0_1_5_4  _0._0_3_2_2
 _2_8.  _N_2 - _H_7 *  -_0._0_0_1_0   _0._0_0_5_1  -_0._0_0_4_7   _0._0_1_8_2  -_0._0_1_7_9
_0._0_1_2_2  _0._0_1_5_4 -_0._0_3_2_2

         _N_B_O         _9       _1_0       _1_1        _1_2        _1_3
_1_4      _1_5
     ---------- ------- ------- ------- ------- -------  ---
---- -------
  _1.  _C_1 - _N_2     _0._1_0_6_2  -_0._0_1_4_3   _0._0_0_0_6   _0._0_0_0_0   _0._0_0_4_9
_0._0_0_0_0 -_0._0_0_6_1
  _2.  _C_1 - _H_3    -_0._3_3_4_3  -_0._0_0_4_4   _0._0_0_1_5   _0._0_0_0_0   _0._0_0_0_7
_0._0_0_0_0 -_0._0_0_8_0
  _3.  _C_1 - _H_4    -_0._1_1_8_6  -_0._0_1_8_6   _0._0_1_0_3   _0._0_2_5_8  -_0._0_0_4_8
-_0._0_2_7_2 -_0._0_1_0_4
  _4.  _C_1 - _H_5    -_0._1_1_8_6  -_0._0_1_8_6   _0._0_1_0_3  -_0._0_2_5_8  -_0._0_0_4_8
_0._0_2_7_2 -_0._0_1_0_4
  _5.  _N_2 - _H_6    -_0._1_1_6_7  -_0._0_0_2_4  -_0._0_1_4_5  -_0._0_2_9_3  -_0._0_1_6_2
-_0._0_2_5_3  _0._0_0_4_0
  _6.  _N_2 - _H_7    -_0._1_1_6_7  -_0._0_0_2_4  -_0._0_1_4_5   _0._0_2_9_3  -_0._0_1_6_2
_0._0_2_5_3  _0._0_0_4_0
  _7.  _C_1 (_c_r)     _0._0_0_3_7  -_0._0_1_3_4  -_0._0_0_8_2   _0._0_0_0_0   _0._0_0_0_8
_0._0_0_0_0 -_0._0_0_0_8
  _8.  _N_2 (_c_r)    -_0._0_1_8_9  -_0._0_0_5_5   _0._0_0_3_0   _0._0_0_0_0  -_0._0_0_2_6
_0._0_0_0_0  _0._0_0_3_5
  _9.  _N_2 (_l_p)     _0._9_0_0_7  -_0._0_1_4_4   _0._0_0_5_5   _0._0_0_0_0   _0._0_9_2_5
_0._0_0_0_0  _0._0_1_3_0
 _1_0.  _C_1 (_r_y*)   -_0._0_1_2_8  -_0._0_9_9_3   _0._0_5_5_3   _0._0_0_0_0   _0._0_5_3_6
_0._0_0_0_0  _0._3_3_0_1
 _1_1.  _C_1 (_r_y*)    _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0   _0._0_8_3_6   _0._0_0_0_0
_0._1_8_4_5  _0._0_0_0_0
 _1_2.  _C_1 (_r_y*)   -_0._0_0_3_9  -_0._0_6_1_2   _0._0_7_4_8   _0._0_0_0_0  -_0._1_1_6_0
_0._0_0_0_0  _0._1_2_1_3
 _1_3.  _C_1 (_r_y*)   -_0._0_0_1_8   _0._0_9_3_6   _0._0_1_9_2   _0._0_0_0_0   _0._1_0_2_2
_0._0_0_0_0 -_0._1_5_1_6
 _1_4.  _N_2 (_r_y*)   -_0._0_0_8_6  -_0._0_2_3_2   _0._0_0_7_1   _0._0_0_0_0  -_0._0_4_6_1
_0._0_0_0_0 -_0._0_1_7_8
 _1_5.  _N_2 (_r_y*)    _0._0_0_0_0   _0._0_0_0_0   _0._0_0_0_0   _0._0_1_7_6   _0._0_0_0_0
-_0._0_8_5_6  _0._0_0_0_0
 _1_6.  _N_2 (_r_y*)    _0._0_0_0_6   _0._0_3_9_5  -_0._0_8_3_6   _0._0_0_0_0   _0._0_2_2_1
_0._0_0_0_0 -_0._1_5_6_5
 _1_7.  _N_2 (_r_y*)    _0._0_0_0_3   _0._0_6_1_4  -_0._0_2_2_2   _0._0_0_0_0   _0._0_1_1_4



                       July 11, 1995





                           - 55 -


_0._0_0_0_0
_0._0_5_8_4
 _1_8.  _H_3 (_r_y*)   -_0._0_2_1_8  -_0._2_4_8_3  -_0._2_2_3_2   _0._0_0_0_0   _0._4_8_2_7
_0._0_0_0_0  _0._0_0_0_1
 _1_9.  _H_4 (_r_y*)    _0._0_0_6_0  -_0._1_9_7_3  -_0._3_2_2_4  -_0._3_3_7_2  -_0._2_0_6_9
-_0._2_1_5_1 -_0._0_4_8_3
 _2_0.  _H_5 (_r_y*)    _0._0_0_6_0  -_0._1_9_7_3  -_0._3_2_2_4   _0._3_3_7_2  -_0._2_0_6_9
_0._2_1_5_1 -_0._0_4_8_3
 _2_1.  _H_6 (_r_y*)    _0._0_0_2_7  -_0._2_8_6_9   _0._2_1_3_2   _0._2_2_9_7  -_0._0_3_7_2
-_0._3_5_4_3 -_0._1_7_3_7
 _2_2.  _H_7 (_r_y*)    _0._0_0_2_7  -_0._2_8_6_9   _0._2_1_3_2  -_0._2_2_9_7  -_0._0_3_7_2
_0._3_5_4_3 -_0._1_7_3_7
 _2_3.  _C_1 - _N_2 *  -_0._0_0_3_1  -_0._2_3_5_7   _0._2_5_9_8   _0._0_0_0_0  -_0._1_0_9_6
_0._0_0_0_0  _0._8_0_5_1
 _2_4.  _C_1 - _H_3 *  -_0._0_7_9_9  -_0._3_2_1_4  -_0._2_6_5_4   _0._0_0_0_0   _0._6_6_8_7
_0._0_0_0_0  _0._1_1_3_3
 _2_5.  _C_1 - _H_4 *  -_0._0_3_6_9   _0._2_5_5_9   _0._3_8_9_0   _0._4_6_9_9   _0._2_9_6_8
_0._3_1_9_3 -_0._0_4_7_7
 _2_6.  _C_1 - _H_5 *  -_0._0_3_6_9   _0._2_5_5_9   _0._3_8_9_0  -_0._4_6_9_9   _0._2_9_6_8
-_0._3_1_9_3 -_0._0_4_7_7
 _2_7.  _N_2 - _H_6 *  -_0._0_0_3_1   _0._4_3_3_9  -_0._3_1_1_2  -_0._3_2_8_0   _0._0_4_7_4
_0._4_5_1_9  _0._2_1_6_8
 _2_8.  _N_2 - _H_7 *  -_0._0_0_3_1   _0._4_3_3_9  -_0._3_1_1_2   _0._3_2_8_0   _0._0_4_7_4
-_0._4_5_1_9  _0._2_1_6_8

 #_T

@_s_e_g

 #_N

_0 _I_n _t_h_i_s _t_r_a_n_s_f_o_r_m_a_t_i_o_n _m_a_t_r_i_x, _r_o_w_s _c_o_r_r_e_s_p_o_n_d _t_o _N_B_O_s _a_n_d
_c_o_l_u_m_n_s  _t_o _M_O_s (_i_n _t_h_e _o_r_d_e_r_i_n_g _u_s_e_d _e_l_e_s_e_w_h_e_r_e _i_n _t_h_e _p_r_o_-
_g_r_a_m), _a_n_d _e_a_c_h _b_a_s_i_s _N_B_O _i_s _f_u_r_t_h_e_r _i_d_e_n_t_i_f_i_e_d _w_i_t_h  _a  _r_o_w
_l_a_b_e_l.   _T_h_e _p_r_i_n_t _p_a_r_a_m_e_t_e_r ``_P_V_A_L'' _s_p_e_c_i_f_i_e_d _t_h_a_t _o_n_l_y _1_5
_M_O_s (_t_h_e _n_u_m_b_e_r  _o_f  _c_o_r_e  +  _v_a_l_e_n_c_e  _o_r_b_i_t_a_l_s)  _s_h_o_u_l_d  _b_e
_p_r_i_n_t_e_d,  _c_o_r_r_e_s_p_o_n_d_i_n_g _t_o _t_h_e _n_i_n_e _o_c_c_u_p_i_e_d _M_O_s _1-_9 _a_n_d _t_h_e
_l_o_w_e_s_t _s_i_x _v_i_r_t_u_a_l _M_O_s _1_0-_1_5.  _T_h_e _m_a_t_r_i_x _a_l_l_o_w_s _o_n_e _t_o  _s_e_e
_t_h_e  _c_o_m_p_o_s_i_t_i_o_n  _o_f _e_a_c_h _c_a_n_o_n_i_c_a_l _M_O _i_n _t_e_r_m_s _o_f _l_o_c_a_l_i_z_e_d
_b_o_n_d _N_B_O_s.  _F_o_r _e_x_a_m_p_l_e, _M_O_s _5 _a_n_d _8  _c_a_n  _b_e  _a_p_p_r_o_x_i_m_a_t_e_l_y
_d_e_s_c_r_i_b_e_d _a_s

_h_i #_d_5#_u ~=  _m_i_n_u_s _0._5_9_4_n  + _0._3_8_1_c

_h_i #_d_8#_u ~=  _0._3_8_1_n  + _0._5_9_4_c

_w_h_e_r_e_a_s                                                   _h_i
#_d_6#_u    _i_s    _p_r_i_m_a_r_i_l_y    _t_h_e    _C-_H(_3)    _N_B_O    _a_n_d   _h_i
#_d_9#_u _t_h_e _N _l_o_n_e _p_a_i_r _N_B_O.  #_I_B._6._5 _B_N_D_I_D_X _K_e_y_w_o_r_d#_N

_0 _T_h_e _B_N_D_I_D_X _k_e_y_w_o_r_d _a_c_t_i_v_a_t_e_s _t_h_e _p_r_i_n_t_i_n_g _o_f _s_e_v_e_r_a_l _t_y_p_e_s
_o_f  `_b_o_n_d  _o_r_d_e_r'  _a_n_d  _v_a_l_e_n_c_y  _i_n_d_i_c_e_s, _b_a_s_e_d _o_n _d_i_f_f_e_r_e_n_t
_a_s_s_u_m_p_t_i_o_n_s _a_n_d _f_o_r_m_u_l_a_s, _b_u_t _a_l_l _h_a_v_i_n_g _s_o_m_e _c_o_n_n_e_c_t_i_o_n  _t_o
_t_h_e  _N_A_O/_N_B_O/_N_L_M_O _f_o_r_m_a_l_i_s_m.  _W_e _i_l_l_u_s_t_r_a_t_e _t_h_e_s_e _b_o_n_d _o_r_d_e_r



                       July 11, 1995





                           - 56 -


_t_a_b_l_e_s
_f_o_r _t_h_e _e_x_a_m_p_l_e _o_f _R_H_F/_3-_2_1_G _m_e_t_h_y_l_a_m_i_n_e (_S_e_c_t_i_o_n _A._3).

_0 _T_h_e _f_i_r_s_t _s_e_g_m_e_n_t _o_f _B_N_D_I_D_X _o_u_t_p_u_t _s_h_o_w_s _t_h_e  _W_i_b_e_r_g  _b_o_n_d
_i_n_d_e_x  (_t_h_e  _s_u_m  _o_f  _s_q_u_a_r_e_s _o_f _o_f_f-_d_i_a_g_o_n_a_l _d_e_n_s_i_t_y _m_a_t_r_i_x
_e_l_e_m_e_n_t_s _b_e_t_w_e_e_n _a_t_o_m_s), _a_s _f_o_r_m_u_l_a_t_e_d _i_n _t_e_r_m_s _o_f  _t_h_e  _N_A_O
_b_a_s_i_s _s_e_t:
_W_i_b_e_r_g _b_o_n_d _i_n_d_e_x _m_a_t_r_i_x _i_n _t_h_e _N_A_O _b_a_s_i_s:

    _A_t_o_m     _1        _2        _3        _4        _5         _6
_7
    ---- ------  ------  ------  ------  ------  ------   --
----
  _1.  _C  _0._0_0_0_0   _0._9_9_6_4   _0._9_4_7_2   _0._9_3_9_4   _0._9_3_9_4   _0._0_0_2_0
_0._0_0_2_0
  _2.  _N  _0._9_9_6_4   _0._0_0_0_0   _0._0_2_0_8   _0._0_0_5_2   _0._0_0_5_2   _0._8_6_1_1
_0._8_6_1_1
  _3.  _H  _0._9_4_7_2   _0._0_2_0_8   _0._0_0_0_0   _0._0_0_0_4   _0._0_0_0_4   _0._0_0_0_2
_0._0_0_0_2
  _4.  _H  _0._9_3_9_4   _0._0_0_5_2   _0._0_0_0_4   _0._0_0_0_0   _0._0_0_0_9   _0._0_0_7_9
_0._0_0_0_5
  _5.  _H  _0._9_3_9_4   _0._0_0_5_2   _0._0_0_0_4   _0._0_0_0_9   _0._0_0_0_0   _0._0_0_0_5
_0._0_0_7_9
  _6.  _H  _0._0_0_2_0   _0._8_6_1_1   _0._0_0_0_2   _0._0_0_7_9   _0._0_0_0_5   _0._0_0_0_0
_0._0_0_0_3
  _7.  _H  _0._0_0_2_0   _0._8_6_1_1   _0._0_0_0_2   _0._0_0_0_5   _0._0_0_7_9   _0._0_0_0_3
_0._0_0_0_0


_W_i_b_e_r_g _b_o_n_d _i_n_d_e_x, _T_o_t_a_l_s _b_y _a_t_o_m:

    _A_t_o_m    _1
    ---- ------
  _1.  _C  _3._8_2_6_5
  _2.  _N  _2._7_4_9_9
  _3.  _H  _0._9_6_9_1
  _4.  _H  _0._9_5_4_4
  _5.  _H  _0._9_5_4_4
  _6.  _H  _0._8_7_2_0
  _7.  _H  _0._8_7_2_0

 #_T

@_s_e_g

 #_N


_0 _T_h_i_s _i_n_d_e_x _i_s _i_n_t_r_i_n_s_i_c_a_l_l_y _a _p_o_s_i_t_i_v_e _q_u_a_n_t_i_t_y, _m_a_k_i_n_g _n_o
_d_i_s_t_i_n_c_t_i_o_n  _b_e_t_w_e_e_n _n_e_t _b_o_n_d_i_n_g _o_r _a_n_t_i_b_o_n_d_i_n_g _c_h_a_r_a_c_t_e_r _o_f
_t_h_e _d_e_n_s_i_t_y _m_a_t_r_i_x _e_l_e_m_e_n_t_s.

_0 _T_h_e _n_e_x_t _s_e_g_m_e_n_t _t_a_b_u_l_a_t_e_s _t_h_e ``_o_v_e_r_l_a_p-_w_e_i_g_h_t_e_d _N_A_O _b_o_n_d
_o_r_d_e_r,'' _a_s _s_h_o_w_n _b_e_l_o_w:



                       July 11, 1995





                           - 57 -


_A_t_o_m-_a_t_o_m _o_v_e_r_l_a_p-_w_e_i_g_h_t_e_d _N_A_O _b_o_n_d _o_r_d_e_r:

    _A_t_o_m     _1        _2        _3        _4        _5         _6
_7
    ---- ------  ------  ------  ------  ------  ------   --
----
  _1.  _C  _0._0_0_0_0   _0._7_8_1_5   _0._7_6_1_4   _0._7_6_3_3   _0._7_6_3_3  -_0._0_1_0_3
-_0._0_1_0_3
  _2.  _N  _0._7_8_1_5   _0._0_0_0_0  -_0._0_2_2_5  -_0._0_0_9_7  -_0._0_0_9_7   _0._6_6_8_8
_0._6_6_8_8
  _3.  _H  _0._7_6_1_4  -_0._0_2_2_5   _0._0_0_0_0  -_0._0_0_3_9  -_0._0_0_3_9  -_0._0_0_1_9
-_0._0_0_1_9
  _4.  _H  _0._7_6_3_3  -_0._0_0_9_7  -_0._0_0_3_9   _0._0_0_0_0   _0._0_0_2_4   _0._0_0_3_8
-_0._0_0_3_2
  _5.  _H  _0._7_6_3_3  -_0._0_0_9_7  -_0._0_0_3_9   _0._0_0_2_4   _0._0_0_0_0  -_0._0_0_3_2
_0._0_0_3_8
  _6.  _H -_0._0_1_0_3   _0._6_6_8_8  -_0._0_0_1_9   _0._0_0_3_8  -_0._0_0_3_2   _0._0_0_0_0
-_0._0_0_6_9
  _7.  _H -_0._0_1_0_3   _0._6_6_8_8  -_0._0_0_1_9  -_0._0_0_3_2   _0._0_0_3_8  -_0._0_0_6_9
_0._0_0_0_0


_A_t_o_m-_a_t_o_m _o_v_e_r_l_a_p-_w_e_i_g_h_t_e_d _N_A_O _b_o_n_d _o_r_d_e_r, _T_o_t_a_l_s _b_y _a_t_o_m:

    _A_t_o_m    _1
    ---- ------
  _1.  _C  _3._0_4_8_8
  _2.  _N  _2._0_7_7_2
  _3.  _H  _0._7_2_7_3
  _4.  _H  _0._7_5_2_7
  _5.  _H  _0._7_5_2_7
  _6.  _H  _0._6_5_0_3
  _7.  _H  _0._6_5_0_3

 #_T

@_s_e_g

 #_N

_0 _T_h_i_s _i_n_d_e_x _c_o_r_r_e_s_p_o_n_d_s _t_o _a _s_u_m _o_f _o_f_f-_d_i_a_g_o_n_a_l  _N_A_O  _d_e_n_-
_s_i_t_y  _m_a_t_r_i_x  _e_l_e_m_e_n_t_s _b_e_t_w_e_e_n _a_t_o_m_s, _e_a_c_h _m_u_l_t_i_p_l_i_e_d _b_y _t_h_e
_c_o_r_r_e_s_p_o_n_d_i_n_g _P_N_A_O _o_v_e_r_l_a_p _i_n_t_e_g_r_a_l.

_0 _A_n_o_t_h_e_r _t_y_p_e _o_f _B_N_D_I_D_X _o_u_t_p_u_t _a_p_p_e_a_r_s _i_f _t_h_e _N_L_M_O  _k_e_y_w_o_r_d
_i_s  _i_n_c_l_u_d_e_d,  _s_u_m_m_a_r_i_z_i_n_g  _a _f_o_r_m_a_l ``_N_L_M_O/_N_P_A _b_o_n_d _o_r_d_e_r''
_t_h_a_t _c_a_n _b_e _a_s_s_o_c_i_a_t_e_d _w_i_t_h _e_a_c_h _N_L_M_O:
_I_n_d_i_v_i_d_u_a_l _L_M_O _b_o_n_d _o_r_d_e_r_s _g_r_e_a_t_e_r _t_h_a_n _0._0_0_2 _i_n _m_a_g_n_i_t_u_d_e,
 _w_i_t_h _t_h_e _o_v_e_r_l_a_p _b_e_t_w_e_e_n _t_h_e _h_y_b_r_i_d_s _i_n _t_h_e _N_L_M_O _g_i_v_e_n:

_A_t_o_m _I / _A_t_o_m _J / _N_L_M_O / _B_o_n_d _O_r_d_e_r / _H_y_b_r_i_d _O_v_e_r_l_a_p /
   _1       _2       _1     _0._8_0_0_7_7_4_1       _0._7_3_1_4_3_6_1
   _1       _2       _5     _0._0_0_2_2_6_9_4       _0._1_7_9_6_6_9_6
   _1       _2       _6     _0._0_0_2_2_6_9_4       _0._1_7_9_6_6_9_6



                       July 11, 1995





                           - 58 -


_1       _2       _9     _0._0_0_8_8_0_6_1       _0._3_0_5_3_7_3_0
   _1       _3       _2     _0._8_0_5_1_6_4_7       _0._7_8_6_2_2_6_3
   _1       _3       _9    -_0._0_0_8_8_0_6_1      -_0._5_7_6_2_5_7_5
   _1       _4       _3     _0._7_7_7_2_1_7_9       _0._7_8_7_4_3_1_2
   _1       _4       _5    -_0._0_0_2_2_6_9_4      -_0._5_3_9_6_9_4_7
   _1       _5       _4     _0._7_7_7_2_1_7_9       _0._7_8_7_4_3_1_2
   _1       _5       _6    -_0._0_0_2_2_6_9_4      -_0._5_3_9_6_9_4_7
   _1       _6       _3    -_0._0_0_3_1_6_5_2      -_0._0_9_2_0_5_2_4
   _1       _6       _5     _0._0_0_2_2_6_9_4       _0._0_8_5_2_0_7_0
   _1       _7       _4    -_0._0_0_3_1_6_5_2      -_0._0_9_2_0_5_2_4
   _1       _7       _6     _0._0_0_2_2_6_9_4       _0._0_8_5_2_0_7_0
   _2       _3       _9    -_0._0_0_9_7_8_4_1      -_0._0_9_3_0_2_0_4
   _2       _4       _5    -_0._0_0_2_7_4_3_7      -_0._0_7_0_1_7_1_7
   _2       _5       _6    -_0._0_0_2_7_4_3_7      -_0._0_7_0_1_7_1_7
   _2       _6       _5     _0._6_3_5_8_5_1_2       _0._7_2_8_6_0_6_1
   _2       _7       _6     _0._6_3_5_8_5_1_2       _0._7_2_8_6_0_6_1
   _4       _6       _3     _0._0_0_3_1_6_5_2       _0._0_4_2_9_2_0_2
   _4       _6       _5     _0._0_0_2_7_4_3_7       _0._0_3_9_9_3_5_2
   _5       _7       _4     _0._0_0_3_1_6_5_2       _0._0_4_2_9_2_0_2
   _5       _7       _6     _0._0_0_2_7_4_3_7       _0._0_3_9_9_3_5_2

 #_T

@_s_e_g



#_N_T_h_i_s _N_L_M_O _b_o_n_d _o_r_d_e_r _i_s _c_a_l_c_u_l_a_t_e_d _b_y _t_h_e _m_e_t_h_o_d _d_e_s_c_r_i_b_e_d
_b_y  _A.  _E. _R_e_e_d _a_n_d _P. _v._R. _S_c_h_l_e_y_e_r [#_I_I_n_o_r_g. _C_h_e_m. #_B_2_7#_N,
_3_9_6_9-_3_9_8_7 (_1_9_8_8); #_I_J. _A_m. _C_h_e_m. _S_o_c.#_N (_t_o _b_e  _p_u_b_l_i_s_h_e_d)],
_b_a_s_e_d  _o_n  _t_h_e  _s_h_a_r_e_d _o_c_c_u_p_a_n_c_i_e_s _a_n_d _h_y_b_r_i_d _o_v_e_r_l_a_p_s (_l_a_s_t
_c_o_l_u_m_n) _o_f _N_A_O_s _c_o_m_p_o_s_i_n_g _t_h_e _N_L_M_O.  _I_n _t_h_e _a_b_o_v_e _t_a_b_l_e, _f_o_r
_e_x_a_m_p_l_e,  _N_L_M_O _1 _o_c_c_u_r_s _o_n_l_y _i_n _t_h_e _f_i_r_s_t _l_i_n_e, _c_o_n_t_r_i_b_u_t_i_n_g
_a _b_o_n_d _o_f _f_o_r_m_a_l _o_r_d_e_r _0._8_0_1 _b_e_t_w_e_e_n _C(_1) _a_n_d _N(_2),  _w_h_e_r_e_a_s
_N_L_M_O  _9  (_t_h_e  _n_i_t_r_o_g_e_n  _l_o_n_e  _p_a_i_r)  _c_o_n_t_r_i_b_u_t_e_s  _a  _s_l_i_g_h_t
_s_t_r_e_n_g_t_h_e_n_i_n_g (+_0._0_0_8_8) _o_f _t_h_e _C(_1)-_N(_2) _b_o_n_d,  _a  _w_e_a_k_e_n_i_n_g
(-_0._0_0_8_8)  _o_f _t_h_e _v_i_c_i_n_a_l _C(_1)-_H(_3) _b_o_n_d, _a_n_d _a _s_l_i_g_h_t _n_e_g_a_-
_t_i_v_e _b_o_n_d _o_r_d_e_r (-_0._0_0_9_8) _b_e_t_w_e_e_n _a_t_o_m_s _N(_2), _H(_3).

_0 _T_h_e _N_L_M_O _b_o_n_d _o_r_d_e_r _c_o_n_t_r_i_b_u_t_i_o_n_s _a_r_e _t_h_e_n _s_u_m_m_e_d _f_o_r _e_a_c_h
_a_t_o_m _p_a_i_r _t_o _g_i_v_e _t_h_e _n_e_t _N_L_M_O/_N_P_A _b_o_n_d _o_r_d_e_r_s _s_h_o_w_n _b_e_l_o_w:
_A_t_o_m-_A_t_o_m _N_e_t _L_i_n_e_a_r _N_L_M_O/_N_P_A _B_o_n_d _O_r_d_e_r_s:

    _A_t_o_m     _1        _2        _3        _4        _5         _6
_7
    ---- ------  ------  ------  ------  ------  ------   --
----
  _1.  _C  _0._0_0_0_0   _0._8_1_7_4   _0._7_9_6_0   _0._7_7_3_2   _0._7_7_3_2  -_0._0_0_1_3
-_0._0_0_1_3
  _2.  _N  _0._8_1_7_4   _0._0_0_0_0  -_0._0_1_0_4  -_0._0_0_3_0  -_0._0_0_3_0   _0._6_3_3_7
_0._6_3_3_7
  _3.  _H  _0._7_9_6_0  -_0._0_1_0_4   _0._0_0_0_0  -_0._0_0_2_0  -_0._0_0_2_0   _0._0_0_0_1
_0._0_0_0_1
  _4.  _H  _0._7_7_3_2  -_0._0_0_3_0  -_0._0_0_2_0   _0._0_0_0_0   _0._0_0_2_0   _0._0_0_6_2



                       July 11, 1995





                           - 59 -


_0._0_0_0_0
  _5.  _H  _0._7_7_3_2  -_0._0_0_3_0  -_0._0_0_2_0   _0._0_0_2_0   _0._0_0_0_0   _0._0_0_0_0
_0._0_0_6_2
  _6.  _H -_0._0_0_1_3   _0._6_3_3_7   _0._0_0_0_1   _0._0_0_6_2   _0._0_0_0_0   _0._0_0_0_0
-_0._0_0_0_1
  _7.  _H -_0._0_0_1_3   _0._6_3_3_7   _0._0_0_0_1   _0._0_0_0_0   _0._0_0_6_2  -_0._0_0_0_1
_0._0_0_0_0

 #_T

@_s_e_g



#_N_F_o_r _e_x_a_m_p_l_e, _t_h_e _t_a_b_l_e _a_t_t_r_i_b_u_t_e_s _a _f_o_r_m_a_l _b_o_n_d  _o_r_d_e_r  _o_f
_0._8_1_7_4  _t_o  _t_h_e  _C(_1)-_N(_2)  _b_o_n_d _o_f _m_e_t_h_y_l_a_m_i_n_e, _t_h_e _h_i_g_h_e_s_t
_b_o_n_d _o_r_d_e_r _i_n _t_h_i_s _m_o_l_e_c_u_l_e.  (_T_h_e _h_i_g_h_e_r  _v_a_l_u_e  _f_o_r  _C(_1)-
_H(_3) _t_h_a_n _f_o_r _t_h_e _o_t_h_e_r _t_w_o _C_H _b_o_n_d_s _r_e_f_l_e_c_t_s _a_n _u_n_s_a_t_i_s_f_a_c_-
_t_o_r_y _a_s_p_e_c_t _o_f _t_h_i_s _m_e_t_h_o_d _o_f _a_s_s_e_s_s_i_n_g _b_o_n_d _o_r_d_e_r.)

_0 _T_h_e_s_e _b_o_n_d _i_n_d_i_c_e_s _a_r_e _b_a_s_e_d _o_n _d_i_f_f_e_r_e_n_t _a_s_s_u_m_p_t_i_o_n_s, _a_n_d
_e_a_c_h  _h_a_s  _c_e_r_t_a_i_n  _a_d_v_a_n_t_a_g_e_s  _a_n_d _d_i_s_a_d_v_a_n_t_a_g_e_s.  #_I_C_a_v_e_a_t
_e_m_p_t_o_r!#_N #_I_B._6._6 _R_E_S_O_N_A_N_C_E _K_e_y_w_o_r_d: _B_e_n_z_e_n_e#_N

_0 _W_h_e_n _N_B_O _a_n_a_l_y_s_i_s _i_s _p_e_r_f_o_r_m_e_d _o_n _a _w_a_v_e_f_u_n_c_t_i_o_n _t_h_a_t _c_a_n_-
_n_o_t  _b_e _s_a_t_i_s_f_a_c_t_o_r_i_l_y _l_o_c_a_l_i_z_e_d [_i._e., _i_n _w_h_i_c_h _o_n_e _o_r _m_o_r_e
_N_B_O_s _o_f _t_h_e _n_a_t_u_r_a_l _L_e_w_i_s  _s_t_r_u_c_t_u_r_e  _f_a_i_l  _t_o  _a_c_h_i_e_v_e  _t_h_e
_t_h_r_e_s_h_o_l_d  _o_c_c_u_p_a_n_c_y  (_1._9_0) _f_o_r _a _s_a_t_i_s_f_a_c_t_o_r_y `_p_a_i_r'], _t_h_e
_N_B_O _p_r_o_g_r_a_m  _a_b_o_r_t_s  _w_i_t_h  _a  _m_e_s_s_a_g_e  _i_n_d_i_c_a_t_i_n_g  _t_h_a_t  _t_h_e
_w_a_v_e_f_u_n_c_t_i_o_n  _i_s  _u_n_s_u_i_t_a_b_l_e  _f_o_r  _l_o_c_a_l_i_z_e_d  _a_n_a_l_y_s_i_s.  _F_o_r
_e_x_a_m_p_l_e, _w_h_e_n _b_e_n_z_e_n_e (_R_H_F/_S_T_O-_3_G  _l_e_v_e_l,  _i_d_e_a_l_i_z_e_d  _P_o_p_l_e-
_G_o_r_d_o_n  _g_e_o_m_e_t_r_y)  _i_s  _t_r_e_a_t_e_d _b_y _t_h_e _N_B_O _p_r_o_g_r_a_m _i_n _d_e_f_a_u_l_t
_m_o_d_e, _o_n_e _o_b_t_a_i_n_s _t_h_e _o_u_t_p_u_t:
_N_A_T_U_R_A_L _B_O_N_D _O_R_B_I_T_A_L _A_N_A_L_Y_S_I_S:

                      _O_c_c_u_p_a_n_c_i_e_s         _L_e_w_i_s    _S_t_r_u_c_t_u_r_e
_L_o_w   _H_i_g_h
          _O_c_c.      -------------------    -----------------
_o_c_c   _o_c_c
 _C_y_c_l_e   _T_h_r_e_s_h.   _L_e_w_i_s    _N_o_n-_L_e_w_i_s      _C_R   _B_D   _3_C   _L_P
(_L)                         (_N_L)                         _D_e_v
=============================================================================
  _1(_1)     _1._9_0     _3_8._8_7_4_7_6    _3._1_2_5_2_4       _6   _1_2   _0   _3
_3      _3    _0._4_4
  _2(_2)    _1._9_0    _3_8._8_7_4_7_6    _3._1_2_5_2_4       _6   _1_2    _0    _3
_3                 _3               _0._4_4            ----------
-------------------------------------------------------------------

_O_n_l_y _s_t_r_o_n_g_l_y _d_e_l_o_c_a_l_i_z_e_d _r_e_s_o_n_a_n_c_e _s_t_r_u_c_t_u_r_e_s _c_a_n _b_e _f_o_u_n_d.
_T_h_e _d_e_f_a_u_l_t _p_r_o_c_e_d_u_r_e _i_s _t_o _a_b_o_r_t _t_h_e _N_B_O _s_e_a_r_c_h.

 #_T

@_s_e_g



                       July 11, 1995





                           - 60 -


_0 #_N_W_h_e_n _t_h_e _R_E_S_O_N_A_N_C_E _k_e_y_w_o_r_d _i_s _a_c_t_i_v_a_t_e_d  _f_o_r  _t_h_i_s  _s_a_m_e
_e_x_a_m_p_l_e, _o_n_e _o_b_t_a_i_n_s _a _s_u_m_m_a_r_y _o_f _N_B_O _s_e_a_r_c_h _c_y_c_l_e_s _a_s _s_h_o_w_n
_b_e_l_o_w:
_N_A_T_U_R_A_L _B_O_N_D _O_R_B_I_T_A_L _A_N_A_L_Y_S_I_S:

                      _O_c_c_u_p_a_n_c_i_e_s         _L_e_w_i_s    _S_t_r_u_c_t_u_r_e
_L_o_w   _H_i_g_h
          _O_c_c.      -------------------    -----------------
_o_c_c   _o_c_c
 _C_y_c_l_e   _T_h_r_e_s_h.   _L_e_w_i_s    _N_o_n-_L_e_w_i_s      _C_R   _B_D   _3_C   _L_P
(_L)                         (_N_L)                         _D_e_v
=============================================================================
  _1(_1)     _1._9_0     _3_8._8_7_4_7_6    _3._1_2_5_2_4       _6   _1_2   _0   _3
_3      _3    _0._4_4
  _2(_2)    _1._9_0    _3_8._8_7_4_7_6    _3._1_2_5_2_4       _6   _1_2    _0    _3
_3      _3    _0._4_4
  _3(_1)    _1._8_0    _3_8._8_7_4_7_6    _3._1_2_5_2_4       _6   _1_2    _0    _3
_3      _3    _0._4_4
  _4(_2)    _1._8_0    _3_8._8_7_4_7_6    _3._1_2_5_2_4       _6   _1_2    _0    _3
_3      _3    _0._4_4
  _5(_1)    _1._7_0    _3_8._8_7_4_7_6    _3._1_2_5_2_4       _6   _1_2    _0    _3
_3      _3    _0._4_4
  _6(_2)    _1._7_0    _3_8._8_7_4_7_6    _3._1_2_5_2_4       _6   _1_2    _0    _3
_3      _3    _0._4_4
  _7(_1)    _1._6_0    _4_0._8_7_4_7_6    _1._1_2_5_2_4       _6   _1_5    _0    _0
_0      _3    _0._4_4
  _8(_2)    _1._6_0    _4_0._8_7_4_7_6    _1._1_2_5_2_4       _6   _1_5    _0    _0
_0      _3    _0._4_4
  _9(_1)    _1._5_0    _4_0._8_7_4_7_6    _1._1_2_5_2_4       _6   _1_5    _0    _0
_0      _3    _0._4_4
 _1_0(_2)    _1._5_0    _4_0._8_7_4_7_6    _1._1_2_5_2_4       _6   _1_5    _0    _0
_0      _3    _0._4_4
 _1_1(_1)    _1._6_0    _4_0._8_7_4_7_6    _1._1_2_5_2_4       _6   _1_5    _0    _0
_0                 _3               _0._4_4            ----------
-------------------------------------------------------------------

_S_t_r_u_c_t_u_r_e _a_c_c_e_p_t_e_d: _R_E_S_O_N_A_N_C_E _k_e_y_w_o_r_d _p_e_r_m_i_t_s _s_t_r_o_n_g_l_y _d_e_l_o_-
_c_a_l_i_z_e_d _s_t_r_u_c_t_u_r_e

 #_T

@_s_e_g

 #_N

_0 _A_s _t_h_i_s _t_a_b_l_e _s_h_o_w_s, _t_h_e _o_c_c_u_p_a_n_c_y _t_h_r_e_s_h_o_l_d  _w_a_s  _s_u_c_c_e_s_-
_s_i_v_e_l_y _l_o_w_e_r_e_d _f_r_o_m _1._9_0 _t_o _1._5_0 _b_y _0._1_e _f_o_r _e_a_c_h _c_y_c_l_e, _a_n_d
_t_h_e _N_B_O _s_e_a_r_c_h _r_e_p_e_a_t_e_d.  _I_n _t_h_i_s  _c_a_s_e,  _t_h_e  `_b_e_s_t'  _L_e_w_i_s
_s_t_r_u_c_t_u_r_e (_l_o_w_e_s_t _o_v_e_r_a_l_l _n_o_n-_L_e_w_i_s _o_c_c_u_p_a_n_c_y, _1._1_2_5_2_4_e) _w_a_s
_f_o_u_n_d _i_n _c_y_c_l_e _7, _w_i_t_h _o_c_c_u_p_a_n_c_y _t_h_r_e_s_h#|_o_l_d _1._6_0_e.  _T_h_e _N_B_O
_p_r_o_g_r_a_m  _t_h_e_r_e_f_o_r_e  _r_e_s_e_t  _t_h_e _t_h_r_e_s_h#|_o_l_d _t_o _t_h_i_s _v_a_l_u_e _a_n_d
_c_a_l_c_u_l_a_t_e_d _t_h_e _s_e_t _o_f  _N_B_O_s  _c_o_r_r_e_s_p_o_n_d_i_n_g  _t_o  _t_h_i_s  `_b_e_s_t'
_L_e_w_i_s _s_t_r_u_c_t_u_r_e, _a_s _s_h_o_w_n _b_e_l_o_w:
    (_O_c_c_u_p_a_n_c_y)   _B_o_n_d _o_r_b_i_t_a_l/ _C_o_e_f_f_i_c_i_e_n_t_s/ _H_y_b_r_i_d_s  -----



                       July 11, 1995





                           - 61 -


-----
---------------------------------------------------------------------
  _1. (_1._9_8_9_4_0) _B_D ( _1) _C _1- _C _2
               ( _5_0._0_0%)   _0._7_0_7_1* _C  _1  _s(  _3_4._2_3%)_p  _1._9_2(
_6_5._7_7%)
                                        _0._0_0_0_0        _0._5_8_5_1
-_0._8_1_0_9  _0._0_0_9_7  _0._0_0_0_0
               ( _5_0._0_0%)   _0._7_0_7_1* _C  _2  _s(  _3_4._2_3%)_p  _1._9_2(
_6_5._7_7%)
                                        _0._0_0_0_0        _0._5_8_5_1
_0._8_1_0_9  _0._0_0_9_7  _0._0_0_0_0
  _2. (_1._9_8_9_4_0) _B_D ( _1) _C _1- _C _6
               ( _5_0._0_0%)   _0._7_0_7_1* _C  _1  _s(  _3_4._2_3%)_p  _1._9_2(
_6_5._7_7%)
                                        _0._0_0_0_0        _0._5_8_5_1
_0._4_1_3_8 -_0._6_9_7_4  _0._0_0_0_0
               ( _5_0._0_0%)   _0._7_0_7_1* _C  _6  _s(  _3_4._2_3%)_p  _1._9_2(
_6_5._7_7%)
                                        _0._0_0_0_0        _0._5_8_5_1
-_0._3_9_7_1  _0._7_0_7_1  _0._0_0_0_0
  _3. (_1._6_6_6_6_7) _B_D ( _2) _C _1- _C _6
               (  _5_0._0_0%)    _0._7_0_7_1*   _C   _1   _s(    _0._0_0%)_p
_1._0_0(_1_0_0._0_0%)
                                        _0._0_0_0_0        _0._0_0_0_0
_0._0_0_0_0  _0._0_0_0_0  _1._0_0_0_0
               (  _5_0._0_0%)    _0._7_0_7_1*   _C   _6   _s(    _0._0_0%)_p
_1._0_0(_1_0_0._0_0%)
                                        _0._0_0_0_0        _0._0_0_0_0
_0._0_0_0_0  _0._0_0_0_0  _1._0_0_0_0
  _4. (_1._9_8_9_7_7) _B_D ( _1) _C _1- _H _7
               ( _5_1._7_3%)   _0._7_1_9_3* _C  _1  _s(  _3_1._5_3%)_p  _2._1_7(
_6_8._4_7%)
                                        0.0000        0.5615
0.4137  0.7166  0.0000
               ( 48.27%)   0.6947* H 7 s(100.00%)
                                        1.0000
  5. (1.98940) BD ( 1) C 2- C 3
               ( 50.00%)   0.7071* C  2  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
-0.4138 -0.6974  0.0000
               ( 50.00%)   0.7071* C  3  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.3971  0.7071  0.0000
  6. (1.66667) BD ( 2) C 2- C 3
               (  50.00%)    0.7071*   C   2   s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000
               (  50.00%)    0.7071*   C   3   s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000



                       July 11, 1995





                           - 62 -


7. (1.98977) BD ( 1) C 2- H 8
               ( 51.73%)   0.7193* C  2  s(  31.53%)p  2.17(
68.47%)
                                        0.0000        0.5615
-0.4137  0.7166  0.0000
               ( 48.27%)   0.6947* H 8 s(100.00%)
                                        1.0000
  8. (1.98940) BD ( 1) C 3- C 4
               ( 50.00%)   0.7071* C  3  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.3971 -0.7071  0.0000
               ( 50.00%)   0.7071* C  4  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
-0.4138  0.6974  0.0000
  9. (1.98977) BD ( 1) C 3- H 9
               ( 51.73%)   0.7193* C  3  s(  31.53%)p  2.17(
68.47%)
                                        0.0000        0.5615
-0.8275  0.0000  0.0000
               ( 48.27%)   0.6947* H 9 s(100.00%)
                                        1.0000
 10. (1.66667) BD ( 2) C 4- C 5
               (  50.00%)    0.7071*   C   4   s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000
               (  50.00%)    0.7071*   C   5   s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000
 11. (1.98940) BD ( 1) C 4- C 5
               ( 50.00%)   0.7071* C  4  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.8109 -0.0097  0.0000
               ( 50.00%)   0.7071* C  5  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
-0.8109 -0.0097  0.0000
 12. (1.98977) BD ( 1) C 4- H10
               ( 51.73%)   0.7193* C  4  s(  31.53%)p  2.17(
68.47%)
                                        0.0000        0.5615
-0.4137 -0.7166  0.0000
               ( 48.27%)   0.6947* H10 s(100.00%)
                                        1.0000
 13. (1.98940) BD ( 1) C 5- C 6
               ( 50.00%)   0.7071* C  5  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.4138  0.6974  0.0000
               ( 50.00%)   0.7071* C  6  s(  34.23%)p  1.92(



                       July 11, 1995





                           - 63 -


65.77%)
                                        0.0000        0.5851
-0.3971 -0.7071  0.0000
 14. (1.98977) BD ( 1) C 5- H11
               ( 51.73%)   0.7193* C  5  s(  31.53%)p  2.17(
68.47%)
                                        0.0000        0.5615
0.4137 -0.7166  0.0000
               ( 48.27%)   0.6947* H11 s(100.00%)
                                        1.0000
 15. (1.98977) BD ( 1) C 6- H12
               ( 51.73%)   0.7193* C  6  s(  31.53%)p  2.17(
68.47%)
                                        0.0000        0.5615
0.8275  0.0000  0.0000
               ( 48.27%)   0.6947* H12 s(100.00%)
                                        1.0000
 16. (1.99995) CR ( 1) C 1             s(100.00%)
                                        1.0000        0.0000
0.0000  0.0000  0.0000
 17. (1.99995) CR ( 1) C 2             s(100.00%)
                                        1.0000        0.0000
0.0000  0.0000  0.0000
 18. (1.99995) CR ( 1) C 3             s(100.00%)
                                        1.0000        0.0000
-0.0001  0.0000  0.0000
 19. (1.99995) CR ( 1) C 4             s(100.00%)
                                        1.0000        0.0000
0.0000  0.0000  0.0000
 20. (1.99995) CR ( 1) C 5             s(100.00%)
                                        1.0000        0.0000
0.0000  0.0000  0.0000
 21. (1.99995) CR ( 1) C 6             s(100.00%)
                                        1.0000        0.0000
0.0001  0.0000  0.0000
 22. (0.01077) BD*( 1) C 1- C 2
               ( 50.00%)   0.7071* C  1  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
-0.8109  0.0097  0.0000
               ( 50.00%)  -0.7071* C  2  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.8109  0.0097  0.0000
 23. (0.01077) BD*( 1) C 1- C 6
               ( 50.00%)   0.7071* C  1  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.4138 -0.6974  0.0000
               ( 50.00%)  -0.7071* C  6  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
-0.3971  0.7071  0.0000
 24. (0.33333) BD*( 2) C 1- C 6



                       July 11, 1995





                           - 64 -


( 50.00%)   0.7071* C 1 s(  0.00%)p 1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000
               (  50.00%)   -0.7071*   C   6   s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000
 25. (0.01011) BD*( 1) C 1- H 7
               ( 48.27%)   0.6947* C  1  s(  31.53%)p  2.17(
68.47%)
                                        0.0000       -0.5615
-0.4137 -0.7166  0.0000
               ( 51.73%)  -0.7193* H 7 s(100.00%)
                                       -1.0000
 26. (0.01077) BD*( 1) C 2- C 3
               ( 50.00%)   0.7071* C  2  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
-0.4138 -0.6974  0.0000
               ( 50.00%)  -0.7071* C  3  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.3971  0.7071  0.0000
 27. (0.33333) BD*( 2) C 2- C 3
               (  50.00%)    0.7071*   C   2   s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000
               (  50.00%)   -0.7071*   C   3   s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000
 28. (0.01011) BD*( 1) C 2- H 8
               ( 48.27%)   0.6947* C  2  s(  31.53%)p  2.17(
68.47%)
                                        0.0000       -0.5615
0.4137 -0.7166  0.0000
               ( 51.73%)  -0.7193* H 8 s(100.00%)
                                       -1.0000
 29. (0.01077) BD*( 1) C 3- C 4
               ( 50.00%)   0.7071* C  3  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.3971 -0.7071  0.0000
               ( 50.00%)  -0.7071* C  4  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
-0.4138  0.6974  0.0000
 30. (0.01011) BD*( 1) C 3- H 9
               ( 48.27%)   0.6947* C  3  s(  31.53%)p  2.17(
68.47%)
                                        0.0000       -0.5615
0.8275  0.0000  0.0000
               ( 51.73%)  -0.7193* H 9 s(100.00%)



                       July 11, 1995





                           - 65 -


-1.0000
 31. (0.33333) BD*( 2) C 4- C 5
               (  50.00%)    0.7071*   C   4   s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000
               (  50.00%)   -0.7071*   C   5   s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  1.0000
 32. (0.01077) BD*( 1) C 4- C 5
               ( 50.00%)   0.7071* C  4  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.8109 -0.0097  0.0000
               ( 50.00%)  -0.7071* C  5  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
-0.8109 -0.0097  0.0000
 33. (0.01011) BD*( 1) C 4- H10
               ( 48.27%)   0.6947* C  4  s(  31.53%)p  2.17(
68.47%)
                                        0.0000       -0.5615
0.4137  0.7166  0.0000
               ( 51.73%)  -0.7193* H10 s(100.00%)
                                       -1.0000
 34. (0.01077) BD*( 1) C 5- C 6
               ( 50.00%)   0.7071* C  5  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
0.4138  0.6974  0.0000
               ( 50.00%)  -0.7071* C  6  s(  34.23%)p  1.92(
65.77%)
                                        0.0000        0.5851
-0.3971 -0.7071  0.0000
 35. (0.01011) BD*( 1) C 5- H11
               ( 48.27%)   0.6947* C  5  s(  31.53%)p  2.17(
68.47%)
                                        0.0000       -0.5615
-0.4137  0.7166  0.0000
               ( 51.73%)  -0.7193* H11 s(100.00%)
                                       -1.0000
 36. (0.01011) BD*( 1) C 6- H12
               ( 48.27%)   0.6947* C  6  s(  31.53%)p  2.17(
68.47%)
                                        0.0000       -0.5615
-0.8275  0.0000  0.0000
               ( 51.73%)  -0.7193* H12 s(100.00%)
                                       -1.0000

 #T

@seg




                       July 11, 1995





                           - 66 -


 #N

0 As one can see from this table, the set of  NBOs  obtained
by  the  program  corresponds  to  one of the two equivalent
Kekulcute e structures, with reasonably well  localized  gma
#dCC#u  and  gma #dCH#u NBOs (1.98940 and 1.98977 electrons,
respectively),    but    three    severely    depleted     i
#dCC#u  bonds  (1.66667e)  and  corresponding high occupancy
i *#<#dCC#u antibonds (0.33333e).  Other sections of the NBO
output (not shown) will similarly exhibit the sharp distinc-
tions between benzene and more `typical'  non-aromatic  com-
pounds.

|<<3//18//72//+1//+11>>|7______________________99______________________

#-#BWARNING#N#+

If you attempt to analyze an open-shell wavefunction with an
ESS  method  that  produces  only  the  ``spinless''  (spin-
averaged) density matrix, rather than the  separate  density
matrices  for lpha and777778 t99a999999  s99p99i99n99,9999 t99h777778 job will likely abort, as in the
default benzene example.  However, you  should  #Inot#N  use
the RESONANCE keyword to bypass this abort!  NBO analysis of
an open-shell  spinless  density  matrix  is  a  fundamental
misuse of the program.

#IB.6.7 NOBOND Keyword#N

0 The NOBOND keyword forces the NBO program to  analyze  the
wavefunction in terms of 1-center functions only, thus forc-
ing a description of the bonding in terms of atomic or ionic
hybrids.   The  modifications of NBO output that result from
activating this  keyword  can  be  illustrated  for  the  HF
molecule  (RHF/3-21G//RHF/3-21G level).  This molecule might
be described in terms of a polar covalent  H-F  bond  or  in
terms of ionic H#u+#dhsp F#uminus #d interactions.

0 The default NBO analysis of this example is shown below:
NATURAL BOND ORBITAL ANALYSIS:

                      Occupancies         Lewis    Structure
Low   High
          Occ.      -------------------    -----------------
occ   occ
 Cycle   Thresh.   Lewis    Non-Lewis      CR   BD   3C   LP
(L)                         (NL)                         Dev
=============================================================================
  1(1)     1.90      9.99942    0.00058       1    1   0   3
0                 0               0.00            ----------
-------------------------------------------------------------------

Structure accepted: No low occupancy Lewis orbitals

--------------------------------------------------------



                       July 11, 1995





                           - 67 -


Core                      1.99994 ( 99.997% of   2)
  Valence Lewis             7.99948 ( 99.994% of   8)
 ==================       ============================
  Total Lewis               9.99942 ( 99.994% of  10)
 -----------------------------------------------------
  Valence non-Lewis         0.00000 (  0.000% of  10)
  Rydberg non-Lewis         0.00058 (  0.006% of  10)
 ==================       ============================
  Total non-Lewis           0.00058 (  0.006% of  10)  -----
---------------------------------------------------


    (Occupancy)   Bond orbital/ Coefficients/ Hybrids  -----
-----
---------------------------------------------------------------------
  1. (2.00000) BD ( 1) F 1- H 2
               ( 75.22%)   0.8673* F  1  s(  16.31%)p  5.13(
83.69%)
                                        0.0000        0.4036
0.0158  0.0000  0.0000
                                        0.0000        0.0000
0.9148  0.0001
               ( 24.78%)   0.4978* H 2 s(100.00%)
                                        1.0000  0.0000
  2. (1.99994) CR ( 1) F 1             s(100.00%)
                                        1.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000
  3.  (2.00000)  LP  (  1)  F  1               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  1.0000 -0.0013
                                        0.0000        0.0000
0.0000  0.0000
  4.  (2.00000)  LP  (  2)  F  1               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        1.0000       -0.0013
0.0000  0.0000
  5. (1.99948) LP ( 3) F  1              s(  83.71%)p  0.19(
16.29%)
                                        0.0000        0.9149
-0.0052  0.0000  0.0000
                                        0.0000        0.0000
-0.4036 -0.0062
  6.  (0.00002)  RY*(  1)  F   1               s(    0.00%)p
1.00(100.00%)
  7.  (0.00000)  RY*(  2)  F   1               s(    0.00%)p
1.00(100.00%)
  8.  (0.00000)  RY*(  3)  F   1               s(    0.00%)p
1.00(100.00%)
  9. (0.00000) RY*( 4) F  1              s(  99.97%)p  0.00(



                       July 11, 1995





                           - 68 -


0.03%)
 10. (0.00056) RY*( 1) H 2             s(100.00%)
                                        0.0000  1.0000
 11. (0.00000) BD*( 1) F 1- H 2
               ( 24.78%)   0.4978* F  1  s(  16.31%)p  5.13(
83.69%)
               ( 75.22%)  -0.8673* H 2 s(100.00%)

 #T

@seg

 #N

As the output shows, default NBO analysis leads to  a  polar
covalent  description of HF.  The gma #dHF#u bond, NBO 1, is
formed from a #Ip#N-rich (#Isp#N#u5.13#d) hybrid  on  F  and
the 1#Is#N AO on H, strongly polarized (about 75.22%) toward
F.  This provides a satisfactory Lewis structure, describing
99.994% of the total electron density.

0 When the NOBOND keyword is activated to bypass the  search
for  2-center  bonds,  the  NBO  output is modified as shown
below:

       /NOBOND / : No two-center NBO search


NATURAL BOND ORBITAL ANALYSIS:

                      Occupancies         Lewis    Structure
Low   High
          Occ.      -------------------    -----------------
occ   occ
 Cycle   Thresh.   Lewis    Non-Lewis      CR   BD   3C   LP
(L)                         (NL)                         Dev
=============================================================================
  1(1)     1.00      9.50378    0.49622       1    0   0   4
0                 1               0.75            ----------
-------------------------------------------------------------------

Structure accepted: Search for  bonds  prevented  by  NOBOND
keyword

--------------------------------------------------------
  Core                      1.99993 ( 99.997% of   2)
  Valence Lewis             7.50385 ( 93.798% of   8)
 ==================       ============================
  Total Lewis               9.50378 ( 95.038% of  10)
 -----------------------------------------------------
  Valence non-Lewis         0.49564 (  4.956% of  10)
  Rydberg non-Lewis         0.00058 (  0.006% of  10)
 ==================       ============================
  Total non-Lewis           0.49622 (  4.962% of  10)  -----



                       July 11, 1995





                           - 69 -


---------------------------------------------------
    (Occupancy)   Bond orbital/ Coefficients/ Hybrids  -----
-----
---------------------------------------------------------------------
  1.  (1.99993)  CR  (  1) F 1             s(100.00%)p 0.00(
0.00%)
                                        1.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0001  0.0000
  2.  (2.00000)  LP  (  1)  F  1               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  1.0000 -0.0013
                                        0.0000        0.0000
0.0000  0.0000
  3.  (2.00000)  LP  (  2)  F  1               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        1.0000       -0.0013
0.0000  0.0000
  4. (1.99948) LP ( 3) F  1              s(  83.71%)p  0.19(
16.29%)
                                        0.0000        0.9149
-0.0052  0.0000  0.0000
                                        0.0000        0.0000
-0.4036 -0.0062
  5. (1.50436) LP ( 4) F  1              s(  16.31%)p  5.13(
83.69%)
                                       -0.0001        0.4036
0.0158  0.0000  0.0000
                                        0.0000        0.0000
0.9148  0.0001
  6. (0.49564) LP*( 1) H 2             s(100.00%)
                                        1.0000  0.0000
  7.  (0.00002)  RY*(  1)  F   1               s(    0.00%)p
1.00(100.00%)
  8.  (0.00000)  RY*(  2)  F   1               s(    0.00%)p
1.00(100.00%)
  9.  (0.00000)  RY*(  3)  F   1               s(    0.00%)p
1.00(100.00%)
 10. (0.00000) RY*( 4) F  1              s(  99.97%)p  0.00(
0.03%)
 11. (0.00056) RY*( 1) H 2             s(100.00%)
                                        0.0000  1.0000

 #T

@seg

 #N

0 In this case, the NBO output indicates a rather poor Lewis



                       July 11, 1995





                           - 70 -


structure
(4.962%  non-Lewis  density),  with  a   severely   depleted
F#uminus #d lone pair (NBO 5, the #Isp#N#u5.13#d hybrid) and
significant occupancy (about 0.496e) in the  `empty'  H#u+#d
1#Is#N orbital (NBO 6) of the cation.  The NOBOND comparison
would therefore indicate the superiority of a polar covalent
description   in   this   case.    #IB.6.8  3CBOND  Keyword:
Diborane#N

0 When the default NBO analysis is applied  to  diborane  or
related  electron-deficient  compounds,  there is a dramatic
failure to represent the electronic distribution in terms of
1-   and   2-center   functions   only.   For  example,  for
B#d2#uH#d6#u at the RHF/3-21G//RHF/3-21G level, the  default
NBO  search  (if the RESONANCE keyword is activated to allow
NBO printout) returns  a  fractured  set  of  4  units  (two
BH#d2#u#u+#d and two H#uminus #d fragments), with about 2.13
electrons unaccounted for (~15% non-Lewis occupancy),  symp-
tomatic  of  general  breakdown  of  the  conventional Lewis
structure representation.

0 However, when the NBO search is extended to 3-center bonds
by activating the 3CBOND keyword, one obtains the NBO output
shown below:

       /3CBOND / : Search for 3-center bonds

NATURAL BOND ORBITAL ANALYSIS:

                      Occupancies         Lewis    Structure
Low   High
          Occ.      -------------------    -----------------
occ   occ
 Cycle   Thresh.   Lewis    Non-Lewis      CR   BD   3C   LP
(L)                         (NL)                         Dev
=============================================================================
  1(1)     1.90     15.94335    0.05665       2    4   2   0
0      0    0.15
  2(2)    1.90    15.94335    0.05665       2    4    2    0
0                 0               0.15            ----------
-------------------------------------------------------------------

Structure accepted: No low occupancy Lewis orbitals

WARNING:  1 low occupancy (<1.9990e) core orbital  found  on
B 1
          1 low occupancy (<1.9990e) core orbital  found  on
B 2

--------------------------------------------------------
  Core                      3.99702 ( 99.925% of   4)
  Valence Lewis            11.94633 ( 99.553% of  12)
 ==================       ============================
  Total Lewis              15.94335 ( 99.646% of  16)



                       July 11, 1995





                           - 71 -


-----------------------------------------------------
  Valence non-Lewis         0.04565 (  0.285% of  16)
  Rydberg non-Lewis         0.01100 (  0.069% of  16)
 ==================       ============================
  Total non-Lewis           0.05665 (  0.354% of  16)  -----
---------------------------------------------------


    (Occupancy)   Bond orbital/ Coefficients/ Hybrids  -----
-----
---------------------------------------------------------------------
  1. (1.98467) 3C ( 1) B 1- B 2- H 3
               ( 26.43%)   0.5141* B  1  s(  18.00%)p  4.55(
82.00%)
                                        0.0005        0.4241
0.0124 -0.7067 -0.0245
                                        0.0000        0.0000
0.5657 -0.0007
               ( 26.43%)   0.5141* B  2  s(  18.00%)p  4.55(
82.00%)
                                        0.0005        0.4241
0.0124 -0.7067 -0.0245
                                        0.0000        0.0000
-0.5657  0.0007
               ( 47.14%)   0.6866* H 3 s(100.00%)
                                        1.0000  0.0066
  2. (1.98467) 3C ( 1) B 1- B 2- H 4
               ( 26.43%)   0.5141* B  1  s(  18.00%)p  4.55(
82.00%)
                                        0.0005        0.4241
0.0124  0.7067  0.0245
                                        0.0000        0.0000
0.5657 -0.0007
               ( 26.43%)   0.5141* B  2  s(  18.00%)p  4.55(
82.00%)
                                        0.0005        0.4241
0.0124  0.7067  0.0245
                                        0.0000        0.0000
-0.5657  0.0007
               ( 47.14%)   0.6866* H 4 s(100.00%)
                                        1.0000  0.0066
  3. (1.99425) BD ( 1) B 1- H 6
               ( 48.80%)   0.6985* B  1  s(  31.98%)p  2.13(
68.02%)
                                       -0.0002        0.5655
-0.0061  0.0000  0.0000
                                        0.7067       -0.0243
-0.4239 -0.0222
               ( 51.20%)   0.7156* H 6 s(100.00%)
                                        1.0000  0.0004
  4. (1.99425) BD ( 1) B 1- H 7
               ( 48.80%)   0.6985* B  1  s(  31.98%)p  2.13(
68.02%)
                                       -0.0002        0.5655



                       July 11, 1995





                           - 72 -


-0.0061
0.0000  0.0000
                                       -0.7067        0.0243
-0.4239 -0.0222
               ( 51.20%)   0.7156* H 7 s(100.00%)
                                        1.0000  0.0004
  5. (1.99425) BD ( 1) B 2- H 5
               ( 48.80%)   0.6985* B  2  s(  31.98%)p  2.13(
68.02%)
                                       -0.0002        0.5655
-0.0061  0.0000  0.0000
                                       -0.7067        0.0243
0.4239  0.0222
               ( 51.20%)   0.7156* H 5 s(100.00%)
                                        1.0000  0.0004
  6. (1.99425) BD ( 1) B 2- H 8
               ( 48.80%)   0.6985* B  2  s(  31.98%)p  2.13(
68.02%)
                                       -0.0002        0.5655
-0.0061  0.0000  0.0000
                                        0.7067       -0.0243
0.4239  0.0222
               ( 51.20%)   0.7156* H 8 s(100.00%)
                                        1.0000  0.0004
  7. (1.99851) CR ( 1)  B  1              s(100.00%)p  0.00(
0.00%)
                                        1.0000       -0.0002
0.0000  0.0000  0.0000
                                        0.0000        0.0000
-0.0007  0.0000
  8. (1.99851) CR ( 1)  B  2              s(100.00%)p  0.00(
0.00%)
                                        1.0000       -0.0002
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0007  0.0000
  9.  (0.00147)  RY*(  1)  B   1               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0344        0.9994
0.0000  0.0000
 10. (0.00080) RY*( 2)  B  1              s(   4.02%)p23.87(
95.98%)
                                        0.0000        0.0245
0.1990  0.0000  0.0000
                                        0.0000        0.0000
-0.0214  0.9795
 11. (0.00002) RY*( 3) B  1              s(  96.01%)p  0.04(
3.99%)
 12.  (0.00000)  RY*(  4)  B   1               s(    0.00%)p
1.00(100.00%)
 13.  (0.00147)  RY*(  1)  B   2               s(    0.00%)p
1.00(100.00%)



                       July 11, 1995





                           - 73 -


0.0000  0.0000  0.0000  0.0000  0.0000
                                        0.0344        0.9994
0.0000  0.0000
 14. (0.00080) RY*( 2)  B  2              s(   4.02%)p23.87(
95.98%)
                                        0.0000        0.0245
0.1990  0.0000  0.0000
                                        0.0000        0.0000
0.0214 -0.9795
 15. (0.00002) RY*( 3) B  2              s(  96.01%)p  0.04(
3.99%)
 16.  (0.00000)  RY*(  4)  B   2               s(    0.00%)p
1.00(100.00%)
 17. (0.00181) RY*( 1) H 3             s(100.00%)
                                       -0.0066  1.0000
 18. (0.00181) RY*( 1) H 4             s(100.00%)
                                       -0.0066  1.0000
 19. (0.00070) RY*( 1) H 5             s(100.00%)
                                       -0.0004  1.0000
 20. (0.00070) RY*( 1) H 6             s(100.00%)
                                       -0.0004  1.0000
 21. (0.00070) RY*( 1) H 7             s(100.00%)
                                       -0.0004  1.0000
 22. (0.00070) RY*( 1) H 8             s(100.00%)
                                       -0.0004  1.0000
 23. (0.01464) 3C*( 1) B 1- B 2- H 3
               ( 23.57%)   0.4855* B  1  s(  18.00%)p  4.55(
82.00%)
                                        0.0005        0.4241
0.0124 -0.7067 -0.0245
                                        0.0000        0.0000
0.5657 -0.0007
               ( 23.57%)  -0.4855* B  2  s(  18.00%)p  4.55(
82.00%)
                                       -0.0005       -0.4241
-0.0124  0.7067  0.0245
                                        0.0000        0.0000
0.5657 -0.0007
               ( 52.86%)  -0.7271* H 3 s(100.00%)
                                        1.0000  0.0066
 24. (0.00026) 3C*( 1) B 1- B 2- H 3
               ( 50.00%)   0.7071* B  1  s(  18.00%)p  4.55(
82.00%)
                                       -0.0005       -0.4241
-0.0124  0.7067  0.0245
                                        0.0000        0.0000
-0.5657  0.0007
               ( 50.00%)  -0.7071* B  2  s(  18.00%)p  4.55(
82.00%)
                                       -0.0005       -0.4241
-0.0124  0.7067  0.0245
                                        0.0000        0.0000
0.5657 -0.0007
               (  0.00%)   0.0000* H 3 s(  0.00%)



                       July 11, 1995





                           - 74 -


0.0000  0.0000
 25. (0.01464) 3C*( 1) B 1- B 2- H 4
               ( 23.57%)   0.4855* B  1  s(  18.00%)p  4.55(
82.00%)
                                        0.0005        0.4241
0.0124  0.7067  0.0245
                                        0.0000        0.0000
0.5657 -0.0007
               ( 23.57%)  -0.4855* B  2  s(  18.00%)p  4.55(
82.00%)
                                       -0.0005       -0.4241
-0.0124 -0.7067 -0.0245
                                        0.0000        0.0000
0.5657 -0.0007
               ( 52.86%)  -0.7271* H 4 s(100.00%)
                                        1.0000  0.0066
 26. (0.00026) 3C*( 1) B 1- B 2- H 4
               ( 50.00%)   0.7071* B  1  s(  18.00%)p  4.55(
82.00%)
                                       -0.0005       -0.4241
-0.0124 -0.7067 -0.0245
                                        0.0000        0.0000
-0.5657  0.0007
               ( 50.00%)  -0.7071* B  2  s(  18.00%)p  4.55(
82.00%)
                                       -0.0005       -0.4241
-0.0124 -0.7067 -0.0245
                                        0.0000        0.0000
0.5657 -0.0007
               (  0.00%)   0.0000* H 4 s(  0.00%)
                                        0.0000  0.0000
 27. (0.00396) BD*( 1) B 2- H 5
               ( 51.20%)   0.7156* B  2  s(  31.98%)p  2.13(
68.02%)
                                       -0.0002        0.5655
-0.0061  0.0000  0.0000
                                       -0.7067        0.0243
0.4239  0.0222
               ( 48.80%)  -0.6985* H 5 s(100.00%)
                                        1.0000  0.0004
 28. (0.00396) BD*( 1) B 2- H 8
               ( 51.20%)   0.7156* B  2  s(  31.98%)p  2.13(
68.02%)
                                       -0.0002        0.5655
-0.0061  0.0000  0.0000
                                        0.7067       -0.0243
0.4239  0.0222
               ( 48.80%)  -0.6985* H 8 s(100.00%)
                                        1.0000  0.0004
 29. (0.00396) BD*( 1) B 1- H 6
               ( 51.20%)   0.7156* B  1  s(  31.98%)p  2.13(
68.02%)
                                       -0.0002        0.5655
-0.0061  0.0000  0.0000



                       July 11, 1995





                           - 75 -


0.7067 -0.0243 -0.4239 -0.0222
               ( 48.80%)  -0.6985* H 6 s(100.00%)
                                        1.0000  0.0004
 30. (0.00396) BD*( 1) B 1- H 7
               ( 51.20%)   0.7156* B  1  s(  31.98%)p  2.13(
68.02%)
                                       -0.0002        0.5655
-0.0061  0.0000  0.0000
                                       -0.7067        0.0243
-0.4239 -0.0222
               ( 48.80%)  -0.6985* H 7 s(100.00%)
                                        1.0000  0.0004

 #T

@seg

 #N

0 The resulting NBO Lewis structure  has  improved  signifi-
cantly  [only  0.057e  (0.35%)  non-Lewis  occupancy].   The
structure includes the expected 3-center B-H-B  bonds  (NBOs
1,  2), each with reasonably high occupancy (1.9847e).  Each
3-c bond is composed of  #Ip#N-rich  (#Isp#N#u4.55#d)  boron
hybrids  and  the  hydrogen 1#Is#N NAO, with about 47.14% of
the orbital density on the central hydrogen.  Note that each
3-center  bond  NBO  is associated with #Itwo#N 3-c antibond
NBOs (viz., NBOs 23, 24 for the  first  3-c  bond,  NBO  1),
which contribute in distinct ways to delocalization interac-
tions.  Of course, the accuracy of #Iany#N  molecular  Lewis
structure  might  be  improved slightly by extending the NBO
search to 3-center bonds (thus allowing greater  variational
flexibility  to maximize occupancy), but this example illus-
trates the kind of #Iqualitative#N  improvement  that  indi-
cates  when  3-center  bonds  are needed in the zeroth-order
picture of the bonding.

0 Note that the NBO 3-c label may frequently have the  wrong
`connectivity' (as in the present case, e.g., where ``B 1- B
2- H 3'' is written instead of the more reasonable ``B 1-  H
3-  B  2'').  This is a consequence of the fact that the NBO
algorithms have no inkling of the positions of the atoms  in
space, and thus of which label is more `reasonable.' #IB.6.9
NBO Directed Search ($CHOOSE Keylist)#N

0 To illustrate the  $CHOOSE  keylist  for  a  directed  NBO
search,  we  again make use of the methylamine example (Sec-
tion A.3).  The vicinal #In#N#dN#u7 arr  gma *#<#dCH#u  delo-
calization, to which attention has been repeatedly called in
the examples, may be associated, in resonance theory  terms,
with  the ``double-bond, no-bond'' resonance structure shown
below:
W10R'#-0hsp                 H#d4#u#+hsp                  '//
D11R'H#d5#u'//BD3'N#d2#u#<#+#++#-#-



                       July 11, 1995





                           - 76 -


'//W5R'H#d6#u'//D4R'H#d7#u'>>
nobond



To investigate the suitability of this  resonance  structure
for   describing  the  methylamine  wavefunction,  we  would
specify the $CHOOSE keylist (Section B.4) as follows:
 #T
     $CHOOSE            !double-bond, no-bond resonance
        LONE  3  1  END
        BOND  S 1 4  S 1 5  D 1 2  S 2 6  S 2 7  END
     $END

#NWhen this is included in the input file, the  NBO  program
produces the output shown below:
NATURAL BOND ORBITAL ANALYSIS:

                      Occupancies         Lewis    Structure
Low   High
          Occ.      -------------------    -----------------
occ   occ
 Cycle   Thresh.   Lewis    Non-Lewis      CR   BD   3C   LP
(L)                         (NL)                         Dev
=============================================================================
  1(1)     1.90     16.66741    1.33259       2    6   0   1
1                 2               0.95            ----------
-------------------------------------------------------------------

Structure accepted: NBOs selected via the $CHOOSE keylist

WARNING:  1 low occupancy (<1.9990e) core orbital  found  on
C 1

--------------------------------------------------------
  Core                      3.99853 ( 99.963% of   4)
  Valence Lewis            12.66888 ( 90.492% of  14)
 ==================       ============================
  Total Lewis              16.66741 ( 92.597% of  18)
 -----------------------------------------------------
  Valence non-Lewis         1.30491 (  7.249% of  18)
  Rydberg non-Lewis         0.02768 (  0.154% of  18)
 ==================       ============================
  Total non-Lewis           1.33259 (  7.403% of  18)  -----
---------------------------------------------------


    (Occupancy)   Bond orbital/ Coefficients/ Hybrids  -----
-----
---------------------------------------------------------------------
  1. (1.95945) BD ( 1) C 1- N 2
               (  7.66%)   0.2768*  C  1  s(   0.63%)p99.99(
99.37%)
                                       -0.0001       -0.0770



                       July 11, 1995





                           - 77 -


-0.0186
0.5107 -0.0551
                                        0.8520       -0.0632
0.0000  0.0000
               ( 92.34%)   0.9609* N  2  s(  19.31%)p  4.18(
80.69%)
                                        0.0000        0.4395
-0.0001 -0.1175 -0.0067
                                        0.8905       -0.0110
0.0000  0.0000
  2. (1.93778) BD ( 2) C 1- N 2
               ( 39.14%)   0.6256* C  1  s(  36.80%)p  1.72(
63.20%)
                                       -0.0004       -0.6055
-0.0371 -0.7047 -0.0632
                                        0.3594       -0.0471
0.0000  0.0000
               ( 60.86%)   0.7801* N  2  s(  19.33%)p  4.17(
80.67%)
                                       -0.0001       -0.4396
0.0011  0.8364 -0.0016
                                        0.3271       -0.0137
0.0000  0.0000
  3. (1.98365) BD ( 1) C 1- H 4
               ( 61.02%)   0.7811* C  1  s(  31.10%)p  2.22(
68.90%)
                                        0.0001        0.5577
0.0006 -0.3480  0.0095
                                        0.2603        0.0094
0.7070 -0.0103
               ( 38.98%)   0.6244* H 4 s(100.00%)
                                        1.0000  0.0008
  4. (1.98365) BD ( 1) C 1- H 5
               ( 61.02%)   0.7811* C  1  s(  31.10%)p  2.22(
68.90%)
                                        0.0001        0.5577
0.0006 -0.3480  0.0095
                                        0.2603        0.0094
-0.7070  0.0103
               ( 38.98%)   0.6244* H 5 s(100.00%)
                                        1.0000  0.0008
  5. (1.99491) BD ( 1) N 2- H 6
               ( 68.46%)   0.8274* N  2  s(  30.67%)p  2.26(
69.33%)
                                        0.0000        0.5538
0.0005  0.3785  0.0165
                                       -0.2232        0.0044
-0.7070 -0.0093
               ( 31.54%)   0.5616* H 6 s(100.00%)
                                        1.0000  0.0031
  6. (1.99491) BD ( 1) N 2- H 7
               ( 68.46%)   0.8274* N  2  s(  30.67%)p  2.26(
69.33%)
                                        0.0000        0.5538



                       July 11, 1995





                           - 78 -


0.0005
0.3785  0.0165
                                       -0.2232        0.0044
0.7070  0.0093
               ( 31.54%)   0.5616* H 7 s(100.00%)
                                        1.0000  0.0031
  7. (1.99900) CR ( 1)  C  1              s(100.00%)p  0.00(
0.00%)
                                        1.0000       -0.0003
0.0000 -0.0001  0.0000
                                        0.0002        0.0000
0.0000  0.0000
  8. (1.99953) CR ( 1)  N  2              s(100.00%)p  0.00(
0.00%)
                                        1.0000       -0.0001
0.0000  0.0001  0.0000
                                        0.0000        0.0000
0.0000  0.0000
  9. (0.81453) LP ( 1) H 3             s(100.00%)
                                        1.0000  0.0000
 10. (0.01893) RY*( 1) C  1              s(  10.61%)p  8.42(
89.39%)
                                        0.0000       -0.0737
0.3173 -0.0090  0.7223
                                        0.0971        0.6021
0.0000  0.0000
 11.  (0.00034)  RY*(  2)  C   1               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0146  0.9999
 12. (0.00025) RY*( 3) C  1              s(  57.37%)p  0.74(
42.63%)
                                        0.0000       -0.0012
0.7575 -0.0176  0.1886
                                       -0.0071       -0.6248
0.0000  0.0000
 13. (0.00002) RY*( 4) C  1              s(  32.38%)p  2.09(
67.62%)
 14. (0.00117) RY*( 1)  N  2              s(   1.48%)p66.74(
98.52%)
                                        0.0000       -0.0067
0.1213  0.0062  0.0380
                                        0.0166        0.9917
0.0000  0.0000
 15.  (0.00044)  RY*(  2)  N   2               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
-0.0132  0.9999
 16. (0.00038) RY*( 3) N  2              s(  33.41%)p  1.99(
66.59%)



                       July 11, 1995





                           - 79 -


0.0000  0.0133  0.5779  0.0087 -0.8150
                                       -0.0120       -0.0392
0.0000  0.0000
 17. (0.00002) RY*( 4) N  2              s(  65.14%)p  0.54(
34.86%)
 18. (0.00177) RY*( 1) H 3             s(100.00%)
                                        0.0000  1.0000
 19. (0.00096) RY*( 1) H 4             s(100.00%)
                                       -0.0008  1.0000
 20. (0.00096) RY*( 1) H 5             s(100.00%)
                                       -0.0008  1.0000
 21. (0.00122) RY*( 1) H 6             s(100.00%)
                                       -0.0031  1.0000
 22. (0.00122) RY*( 1) H 7             s(100.00%)
                                       -0.0031  1.0000
 23. (1.02290) BD*( 1) C 1- N 2
               ( 92.34%)   0.9609*  C  1  s(   0.63%)p99.99(
99.37%)
                                       -0.0001       -0.0770
-0.0186  0.5107 -0.0551
                                        0.8520       -0.0632
0.0000  0.0000
               (  7.66%)  -0.2768* N  2  s(  19.31%)p  4.18(
80.69%)
                                        0.0000        0.4395
-0.0001 -0.1175 -0.0067
                                        0.8905       -0.0110
0.0000  0.0000
 24. (0.22583) BD*( 2) C 1- N 2
               ( 60.86%)   0.7801* C  1  s(  36.80%)p  1.72(
63.20%)
                                       -0.0004       -0.6055
-0.0371 -0.7047 -0.0632
                                        0.3594       -0.0471
0.0000  0.0000
               ( 39.14%)  -0.6256* N  2  s(  19.33%)p  4.17(
80.67%)
                                       -0.0001       -0.4396
0.0011  0.8364 -0.0016
                                        0.3271       -0.0137
0.0000  0.0000
 25. (0.01415) BD*( 1) C 1- H 4
               ( 38.98%)   0.6244* C  1  s(  31.10%)p  2.22(
68.90%)
                                       -0.0001       -0.5577
-0.0006  0.3480 -0.0095
                                       -0.2603       -0.0094
-0.7070  0.0103
               ( 61.02%)  -0.7811* H 4 s(100.00%)
                                       -1.0000 -0.0008
 26. (0.01415) BD*( 1) C 1- H 5
               ( 38.98%)   0.6244* C  1  s(  31.10%)p  2.22(
68.90%)
                                       -0.0001       -0.5577



                       July 11, 1995





                           - 80 -


-0.0006
0.3480 -0.0095
                                       -0.2603       -0.0094
0.7070 -0.0103
               ( 61.02%)  -0.7811* H 5 s(100.00%)
                                       -1.0000 -0.0008
 27. (0.01394) BD*( 1) N 2- H 6
               ( 31.54%)   0.5616* N  2  s(  30.67%)p  2.26(
69.33%)
                                        0.0000       -0.5538
-0.0005 -0.3785 -0.0165
                                        0.2232       -0.0044
0.7070  0.0093
               ( 68.46%)  -0.8274* H 6 s(100.00%)
                                       -1.0000 -0.0031
 28. (0.01394) BD*( 1) N 2- H 7
               ( 31.54%)   0.5616* N  2  s(  30.67%)p  2.26(
69.33%)
                                        0.0000       -0.5538
-0.0005 -0.3785 -0.0165
                                        0.2232       -0.0044
-0.7070 -0.0093
               ( 68.46%)  -0.8274* H 7 s(100.00%)
                                       -1.0000 -0.0031

 #T

@seg

 #N

0 One can see that the $CHOOSE resonance structure is signi-
ficantly inferior to the principal resonance structure found
by the default NBO search in Section A.3.  About 1.333e,  or
7.4%  of the electron density, is found in non-Lewis NBOs of
the $CHOOSE structure (compared to 0.05e, or 0.3%,  for  the
principal structure).  Particularly defective is the hydride
`lone pair' (NBO 9), which has less than half  the  expected
occupancy        (0.81453e).         The        C-N        i
bond (NBO 1) is seen to be more than 92% polarized toward N,
indicative of essential lone pair character.

0 Note that structural elements shared by the two  resonance
structures  (e.g.,  the  two  N-H bonds, which are common to
both structures) need not have identical forms,  since  each
detail  of the NBOs is optimized with respect to the overall
structure.  #IB.6.10 NBO Energetic Analysis ($DEL Keylist)#N

0 The NBO energetic analysis with deletions  ($DEL  keylist)
will  be  illustrated with two simple examples for RHF/3-21G
methylamine (Section A.3).

0 The first example is the ``NOSTAR'' option (type  4,  Sec-
tion  B.5),  requesting  deletion of all non-Lewis orbitals,



                       July 11, 1995





                           - 81 -


and
hence leading to the energy of the idealized  natural  Lewis
structure.  The $DEL keylist in this case is
 #T
     $DEL  NOSTAR  $END

#NThis leads to the output shown below:
NOSTAR: Delete all Rydberg/antibond  NBOs  Deletion  of  the
following orbitals from the NBO Fock matrix:
  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24
25  26  27  28

Occupations of bond orbitals:

      Orbital                   No deletions   This deletion
Change                                            ----------
--------------------------------------------------------------------
  1.  BD  ( 1) C 1- N 2               1.99858        2.00000
0.00142
  2. BD ( 1) C 1- H 3                1.99860         2.00000
0.00140
  3. BD ( 1) C 1- H 4                1.99399         2.00000
0.00601
  4. BD ( 1) C 1- H 5                1.99399         2.00000
0.00601
  5. BD ( 1) N 2- H 6                1.99442         2.00000
0.00558
  6. BD ( 1) N 2- H 7                1.99442         2.00000
0.00558
  7. CR ( 1) C 1                     1.99900         2.00000
0.00100
  8. CR ( 1) N 2                     1.99953         2.00000
0.00047
  9. LP ( 1) N 2                     1.97795         2.00000
0.02205
 10. RY*( 1) C 1                     0.00105         0.00000
-0.00105
 11. RY*( 2) C 1                     0.00034         0.00000
-0.00034
 12. RY*( 3) C 1                     0.00022         0.00000
-0.00022
 13. RY*( 4) C 1                     0.00002         0.00000
-0.00002
 14. RY*( 1) N 2                     0.00116         0.00000
-0.00116
 15. RY*( 2) N 2                     0.00044         0.00000
-0.00044
 16. RY*( 3) N 2                     0.00038         0.00000
-0.00038
 17. RY*( 4) N 2                     0.00002         0.00000
-0.00002
 18. RY*( 1) H 3                     0.00178         0.00000
-0.00178
 19. RY*( 1) H 4                     0.00096         0.00000



                       July 11, 1995





                           - 82 -


-0.00096
 20. RY*( 1) H 5                     0.00096         0.00000
-0.00096
 21. RY*( 1) H 6                     0.00122         0.00000
-0.00122
 22. RY*( 1) H 7                     0.00122         0.00000
-0.00122
 23. BD*( 1) C 1- N 2                0.00016         0.00000
-0.00016
 24. BD*( 1) C 1- H 3                0.01569         0.00000
-0.01569
 25. BD*( 1) C 1- H 4                0.00769         0.00000
-0.00769
 26. BD*( 1) C 1- H 5                0.00769         0.00000
-0.00769
 27. BD*( 1) N 2- H 6                0.00426         0.00000
-0.00426
 28. BD*( 1) N 2- H 7                0.00426         0.00000
-0.00426

NEXT STEP:  Evaluate the energy of the new density matrix
            that has been constructed from the deleted NBO
            Fock matrix by doing one SCF cycle.

---------
---------------------------------------------------------------------
  Energy of deletion :        -94.618081014
    Total SCF energy :        -94.679444944
                         -------------------
       Energy    change    :              0.061364     a.u.,
38.506 kcal/mol

 #T

@seg

 #N

0 In the output above, the NBO program first enumerates  the
19  NBOs to be deleted by the ``NOSTAR'' request, then gives
the complete list of  NBOs  with  their  occupancies  before
(``no  deletions'') and after (``this deletion'') deletions,
with the net change for each.   For  this  NOSTAR  deletion,
each  of  the  nine Lewis NBOs (1-9) necessarily gets 2.0000
electrons, and each of the non-Lewis NBOs (10-28) gets occu-
pancy  0.0000.   The  program than reports the energy (minus
94.618081 a.u.) obtained from a single pass through the  SCF
evaluator  with  the modified density matrix.  In this case,
deletion of the 19  non-Lewis  orbitals  led  to  an  energy
change  of  only  0.061364  a.u.  (38.5 kcal/mol), less than
0.07% of the total energy.

0 The next example is a  more  selective  set  of  deletions
between  `chemical fragments' (type 9), selected by the $DEL



                       July 11, 1995





                           - 83 -


keylist
input shown below:
 #T
     $DEL
        ZERO  2  ATOM BLOCKS
                 4  BY  3
                    1  3  4  5
                    2  6  7
                 3  BY  4
                    2  6  7
                    1  3  4  5
     $END

#NThis specifies removal of  all  delocalizing  interactions
from  Lewis NBOs of the methyl fragment (atoms 1,3,4,5) into
non-Lewis NBOs of the amine fragment (atoms 2,6,7), or  vice
versa.  The NBO output for this example is shown below:
Zero delocalization from NBOs localized on atoms:
   1   3   4   5 to NBOs localized on atoms:
   2   6   7
    (NBOs in common to the two groups  of  atoms  left  out)
Zero delocalization from NBOs localized on atoms:
   2   6   7 to NBOs localized on atoms:
   1   3   4   5
    (NBOs in common to the two groups  of  atoms  left  out)
Deletion of the NBO Fock matrix elements between orbitals:
   2   3   4   7 and orbitals:
  14  15  16  17  21  22  27  28 Deletion of  the  NBO  Fock
matrix elements between orbitals:
   5   6   8   9 and orbitals:
  10  11  12  13  18  19  20  24  25  26

Occupations of bond orbitals:

      Orbital                   No deletions   This deletion
Change                                            ----------
--------------------------------------------------------------------
  1.  BD  ( 1) C 1- N 2               1.99858        1.99860
0.00002
  2. BD ( 1) C 1- H 3                1.99860         1.99937
0.00077
  3. BD ( 1) C 1- H 4                1.99399         1.99911
0.00512
  4. BD ( 1) C 1- H 5                1.99399         1.99911
0.00512
  5. BD ( 1) N 2- H 6                1.99442         1.99979
0.00537
  6. BD ( 1) N 2- H 7                1.99442         1.99979
0.00537
  7. CR ( 1) C 1                     1.99900         1.99919
0.00019
  8. CR ( 1) N 2                     1.99953         1.99974
0.00021
  9. LP ( 1) N 2                     1.97795         1.99996



                       July 11, 1995





                           - 84 -


0.02201
 10. RY*( 1) C 1                     0.00105         0.00016
-0.00090
 11. RY*( 2) C 1                     0.00034         0.00000
-0.00033
 12. RY*( 3) C 1                     0.00022         0.00002
-0.00020
 13. RY*( 4) C 1                     0.00002         0.00002
0.00000
 14. RY*( 1) N 2                     0.00116         0.00004
-0.00112
 15. RY*( 2) N 2                     0.00044         0.00000
-0.00044
 16. RY*( 3) N 2                     0.00038         0.00003
-0.00035
 17. RY*( 4) N 2                     0.00002         0.00001
-0.00001
 18. RY*( 1) H 3                     0.00178         0.00088
-0.00090
 19. RY*( 1) H 4                     0.00096         0.00057
-0.00038
 20. RY*( 1) H 5                     0.00096         0.00057
-0.00038
 21. RY*( 1) H 6                     0.00122         0.00057
-0.00065
 22. RY*( 1) H 7                     0.00122         0.00057
-0.00065
 23. BD*( 1) C 1- N 2                0.00016         0.00034
0.00018
 24. BD*( 1) C 1- H 3                0.01569         0.00027
-0.01542
 25. BD*( 1) C 1- H 4                0.00769         0.00055
-0.00714
 26. BD*( 1) C 1- H 5                0.00769         0.00055
-0.00714
 27. BD*( 1) N 2- H 6                0.00426         0.00009
-0.00417
 28. BD*( 1) N 2- H 7                0.00426         0.00009
-0.00417

NEXT STEP:  Evaluate the energy of the new density matrix
            that has been constructed from the deleted NBO
            Fock matrix by doing one SCF cycle.

---------
---------------------------------------------------------------------
  Energy of deletion :        -94.635029232
    Total SCF energy :        -94.679444944
                         -------------------
       Energy    change    :              0.044416     a.u.,
27.871 kcal/mol

 #T




                       July 11, 1995





                           - 85 -


@seg

 #N

0 The output first  lists  the  various  orbitals  and  Fock
matrix elements affected by this deletion, then the `before'
and `after' occupancies and net changes for  each  NBO.   In
this  case,  one  can  see  that the principal effect of the
deletion was increased occupancy (+0.022)  of  the  nitrogen
lone  pair,  NBO  9, and depleted occupancy (minus 0.015) of
the antiperiplanar gma *#<#dC#d1#uH#d3#u#u antibond, NBO 24,
with  somewhat  lesser  depletion (minus 0.007) of the other
two C-H antibonds.  The total energy change (loss  of  delo-
calization  energy)  associated  with this deletion was 27.9
kcal/mol.

0 To further pinpoint the source of this delocalization, one
could  do more selective deletions of individual orbitals or
Fock matrix elements.  For example,  if  one  uses  deletion
type  2  (deletion  of a single Fock matrix element, Section
B.5.2) to delete the  (9,24)  element  associated  with  the
#In#N#dN#u7  arr   gma  *#<#dC#d1#uH#d3#u#u  interaction, one
finds a deletion energy of  7.06  kcal/mol  associated  with
this  interaction  alone.   [This value may be compared with
the  simple   second-order   perturbative   estimate   (8.13
kcal/mol)  of  the  #In#N#dN#u7  arr  gma *#<#dC#d1#uH#d3#u#u
(97arr 24) interaction that  was  noted  in  Section  A.3.5.]
#IB.6.11 Open-Shell UHF Output: Methyl Radical#N

0 Open-shell NBO output will be illustrated with the  simple
example  of  the planar methyl radical (CH#d3#u), treated at
the UHF/6-31G* level (#IR#N#dCH#u = 1.0736hsp ngstrom ).  In
the  open-shell  case,  one obtains two separate NPA and NBO
listings, one for  the  lpha   and  one  for  the77778  t99a999999    s99p99i99n9999  s77778t,
corresponding  to  the ``different Lewis structures for dif-
ferent spins'' description.  A portion of the NBO output for
the lpha  spin manifold is reproduced below:
NATURAL BOND ORBITAL ANALYSIS, alpha spin orbitals:

                      Occupancies         Lewis    Structure
Low   High
          Occ.      -------------------    -----------------
occ   occ
 Cycle   Thresh.   Lewis    Non-Lewis      CR   BD   3C   LP
(L)                         (NL)                         Dev
=============================================================================
  1(1)     0.90      4.99903    0.00097       1    3   0   1
0                 0               0.00            ----------
-------------------------------------------------------------------

Structure accepted: No low occupancy Lewis orbitals

--------------------------------------------------------
  Core                      0.99984 ( 99.984% of   1)



                       July 11, 1995





                           - 86 -


Valence Lewis             3.99919 ( 99.980% of   4)
 ==================       ============================
  Total Lewis               4.99903 ( 99.981% of   5)
 -----------------------------------------------------
  Valence non-Lewis         0.00081 (  0.016% of   5)
  Rydberg non-Lewis         0.00016 (  0.003% of   5)
 ==================       ============================
  Total non-Lewis           0.00097 (  0.019% of   5)  -----
---------------------------------------------------


    (Occupancy)   Bond orbital/ Coefficients/ Hybrids  -----
-----
---------------------------------------------------------------------
  1. (0.99973) BD ( 1) C 1- H 2
               ( 61.14%)   0.7819* C  1  s(  33.33%)p  2.00(
66.51%)d 0.00(  0.16%)
                                        0.0000        0.5772
-0.0070  0.0000 -0.4076
                                       -0.0110        0.7060
0.0191  0.0000  0.0000
                                       -0.0338        0.0000
0.0000 -0.0195 -0.0090
               ( 38.86%)   0.6233* H 2 s(100.00%)
                                        1.0000  0.0080
  2. (0.99973) BD ( 1) C 1- H 3
               ( 61.14%)   0.7819* C  1  s(  33.33%)p  2.00(
66.51%)d 0.00(  0.16%)
                                        0.0000        0.5772
-0.0070  0.0000 -0.4076
                                       -0.0110       -0.7060
-0.0191  0.0000  0.0000
                                        0.0338        0.0000
0.0000 -0.0195 -0.0090
               ( 38.86%)   0.6233* H 3 s(100.00%)
                                        1.0000  0.0080
  3. (0.99973) BD ( 1) C 1- H 4
               ( 61.14%)   0.7819* C  1  s(  33.33%)p  2.00(
66.51%)d 0.00(  0.16%)
                                        0.0000        0.5772
-0.0070  0.0000  0.8153
                                        0.0221        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0391 -0.0090
               ( 38.86%)   0.6233* H 4 s(100.00%)
                                        1.0000  0.0080
  4. (0.99984) CR ( 1) C 1             s(100.00%)
                                        1.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000



                       July 11, 1995





                           - 87 -


5.  (1.00000)  LP  (  1)   C   1               s(    0.00%)p
1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.9978 -0.0668
                                        0.0000        0.0000
0.0000  0.0000  0.0000
  6. (0.00000) RY*( 1)  C  1              s(100.00%)p  0.00(
0.00%)d 0.00(  0.00%)
  7. (0.00000) RY*( 2) C 1             s(100.00%)
  8.  (0.00000)  RY*(  3)  C   1               s(    0.00%)p
1.00(100.00%)d 0.00(  0.00%)
  9.  (0.00000)  RY*(  4)  C   1               s(    0.00%)p
1.00(100.00%)d 0.00(  0.00%)
 10.  (0.00000)  RY*(  5)  C   1               s(    0.00%)p
1.00(100.00%)
 11. (0.00000) RY*( 6) C  1              s(   0.00%)p  1.00(
0.23%)d99.99( 99.77%)
 12. (0.00000) RY*( 7) C  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 13. (0.00000) RY*( 8) C  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 14. (0.00000) RY*( 9) C  1              s(   0.00%)p  1.00(
0.23%)d99.99( 99.77%)
 15. (0.00000) RY*(10) C  1              s(   0.02%)p  0.00(
0.00%)d99.99( 99.98%)
 16. (0.00005) RY*( 1) H 2             s(100.00%)
 17. (0.00005) RY*( 1) H 3             s(100.00%)
 18. (0.00005) RY*( 1) H 4             s(100.00%)
 19. (0.00027) BD*( 1) C 1- H 2
               ( 38.86%)   0.6233* C  1  s(  33.33%)p  2.00(
66.51%)d 0.00(  0.16%)
                                        0.0000       -0.5772
0.0070  0.0000  0.4076
                                        0.0110       -0.7060
-0.0191  0.0000  0.0000
                                        0.0338        0.0000
0.0000  0.0195  0.0090
               ( 61.14%)  -0.7819* H 2 s(100.00%)
                                       -1.0000 -0.0080
 20. (0.00027) BD*( 1) C 1- H 3
               ( 38.86%)   0.6233* C  1  s(  33.33%)p  2.00(
66.51%)d 0.00(  0.16%)
                                        0.0000       -0.5772
0.0070  0.0000  0.4076
                                        0.0110        0.7060
0.0191  0.0000  0.0000
                                       -0.0338        0.0000
0.0000  0.0195  0.0090
               ( 61.14%)  -0.7819* H 3 s(100.00%)
                                       -1.0000 -0.0080
 21. (0.00027) BD*( 1) C 1- H 4
               ( 38.86%)   0.6233* C  1  s(  33.33%)p  2.00(



                       July 11, 1995





                           - 88 -


66.51%)d
0.00(  0.16%)
                                        0.0000       -0.5772
0.0070  0.0000 -0.8153
                                       -0.0221        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000 -0.0391  0.0090
               ( 61.14%)  -0.7819* H 4 s(100.00%)
                                       -1.0000 -0.0080

 #T

@seg

 #N

0 As can be seen in the output, the NBO  spin-orbital  occu-
pancy  threshold was set at 0.90 (rather than 1.90), and the
occupancies of lpha  Lewis spin-NBOs (1-5) are about 1.0000,
but  other  aspects  of  the  output are familiar.  Note the
slight admixture  of  #Id#N-character  (0.16%)  in  the  gma
#dCH#u  bond  hybrids  (NBOs  1-3), whereas the out-of-plane
radical non-bonded orbital (NBO 5) has pure #Ip#N-character.

0 The NBO output for the77777 t99a999999  (99`99i99o99n99i99z77777d') spin set then follows:
NATURAL BOND ORBITAL ANALYSIS, beta spin orbitals:

                      Occupancies         Lewis    Structure
Low   High
          Occ.      -------------------    -----------------
occ   occ
 Cycle   Thresh.   Lewis    Non-Lewis      CR   BD   3C   LP
(L)                         (NL)                         Dev
=============================================================================
  1(1)     0.90      3.99981    0.00019       1    3   0   0
0                 0               0.00            ----------
-------------------------------------------------------------------

Structure accepted: No low occupancy Lewis orbitals

--------------------------------------------------------
  Core                      0.99985 ( 99.985% of   1)
  Valence Lewis             2.99996 ( 99.999% of   3)
 ==================       ============================
  Total Lewis               3.99981 ( 99.995% of   4)
 -----------------------------------------------------
  Valence non-Lewis         0.00002 (  0.000% of   4)
  Rydberg non-Lewis         0.00017 (  0.004% of   4)
 ==================       ============================
  Total non-Lewis           0.00019 (  0.005% of   4)  -----
---------------------------------------------------





                       July 11, 1995





                           - 89 -


    (Occupancy)   Bond orbital/ Coefficients/ Hybrids  -----
-----
---------------------------------------------------------------------
  1. (0.99999) BD ( 1) C 1- H 2
               ( 55.80%)   0.7470* C  1  s(  33.21%)p  2.00(
66.51%)d 0.01(  0.28%)
                                        0.0000        0.5762
0.0080  0.0000 -0.4076
                                       -0.0125        0.7059
0.0217  0.0000  0.0000
                                       -0.0345        0.0000
0.0000 -0.0199 -0.0350
               ( 44.20%)   0.6649* H 2 s(100.00%)
                                        1.0000 -0.0069
  2. (0.99999) BD ( 1) C 1- H 3
               ( 55.80%)   0.7470* C  1  s(  33.21%)p  2.00(
66.51%)d 0.01(  0.28%)
                                        0.0000        0.5762
0.0080  0.0000 -0.4076
                                       -0.0125       -0.7059
-0.0217  0.0000  0.0000
                                        0.0345        0.0000
0.0000 -0.0199 -0.0350
               ( 44.20%)   0.6649* H 3 s(100.00%)
                                        1.0000 -0.0069
  3. (0.99999) BD ( 1) C 1- H 4
               ( 55.80%)   0.7470* C  1  s(  33.21%)p  2.00(
66.51%)d 0.01(  0.28%)
                                        0.0000        0.5762
0.0080  0.0000  0.8151
                                        0.0251        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0399 -0.0350
               ( 44.20%)   0.6649* H 4 s(100.00%)
                                        1.0000 -0.0069
  4. (0.99985) CR ( 1) C 1             s(100.00%)
                                        1.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
  5. (0.00002) LP*( 1) C  1              s(  10.35%)p  0.00(
0.00%)d 8.66( 89.65%)
  6. (0.00000) RY*( 1) C  1              s(  98.99%)p  0.00(
0.00%)d 0.01(  1.01%)
  7.  (0.00000)  RY*(  2)  C   1               s(    0.00%)p
1.00(100.00%)d 0.00(  0.00%)
  8.  (0.00000)  RY*(  3)  C   1               s(    0.00%)p
1.00(100.00%)d 0.00(  0.00%)
  9.  (0.00000)  RY*(  4)  C   1               s(    0.00%)p
1.00(100.00%)
 10.  (0.00000)  RY*(  5)  C   1               s(    0.00%)p



                       July 11, 1995





                           - 90 -


1.00(100.00%)
 11. (0.00000) RY*( 6) C  1              s(   0.00%)p  1.00(
0.24%)d99.99( 99.76%)
 12. (0.00000) RY*( 7) C  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 13. (0.00000) RY*( 8) C  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 14. (0.00000) RY*( 9) C  1              s(   0.00%)p  1.00(
0.24%)d99.99( 99.76%)
 15. (0.00000) RY*(10) C  1              s(  91.02%)p  0.00(
0.00%)d 0.10(  8.98%)
 16. (0.00006) RY*( 1) H 2             s(100.00%)
 17. (0.00006) RY*( 1) H 3             s(100.00%)
 18. (0.00006) RY*( 1) H 4             s(100.00%)
 19. (0.00000) BD*( 1) C 1- H 2
               ( 44.20%)   0.6649* C  1  s(  33.21%)p  2.00(
66.51%)d 0.01(  0.28%)
               ( 55.80%)  -0.7470* H 2 s(100.00%)
 20. (0.00000) BD*( 1) C 1- H 3
               ( 44.20%)   0.6649* C  1  s(  33.21%)p  2.00(
66.51%)d 0.01(  0.28%)
               ( 55.80%)  -0.7470* H 3 s(100.00%)
 21. (0.00000) BD*( 1) C 1- H 4
               ( 44.20%)   0.6649* C  1  s(  33.21%)p  2.00(
66.51%)d 0.01(  0.28%)
               ( 55.80%)  -0.7470* H 4 s(100.00%)

 #T

@seg

 #N

0 The principal difference to be seen is  that  the  radical
orbital  (NBO  5) is essentially empty in this spin set, and
the polarization of the gma #dCH#u bonds is somewhat altered
(about 55.8% on the C atom in the77 t99a999999  s77t set, #Ivs.#N 61.1% in
the lpha  set).  [In other cases, the lpha   and7777  t99a999999    N99B99O9999  L7777wis
structures  might  differ even in the number and location of
1-c (non-bonding) and 2-c (bond) structural elements.]  Note
that  the  overall  quality  of the open-shell natural Lewis
structure description (> 99.9%) is  comparable  to  that  of
ordinary  closed-shell  molecules, and the interpretation of
the NBO output follows familiar lines.

|<<3//18//72//+1//+11>>|7______________________99______________________

#-#BWARNING#N#+

You should not attempt to analyze an open-shell wavefunction
with  an  ESS  method  that  produces  only the ``spinless''
(spin-averaged) density matrix,  rather  than  the  separate
density  matrices  for lpha and777777777777777 t99a999999  s99p99i99n99.999999  A99l99t99h99o99u99g99h9999 N99A99O99s9999 a99n99d9999 t99h777777777777777ir total populations
are calculated correctly from the spinless  density  matrix,



                       July 11, 1995





                           - 91 -


NBOs
and NLMOs are not.  NBO analysis of an  open-shell  spinless
density  matrix  is  a  fundamental  misuse  of the program.
#IB.6.12 Effective Core Potential: Cu#d2#u Dimer#N

0 To illustrate some of the variations of NBO output associ-
ated  with use of effective core potentials (ECP) and inclu-
sion of #Id#N orbitals, we use the  example  of  the  copper
dimer  Cu#d2#u  (#IR#N = 2.2195hsp ngstrom ), treated at the
RHF  level  with  a  Hay-Wadt  ECP  and  valence  DZ   basis
(RHF/LANL1DZ),  carried  out  with  the  GAUSSIAN-88 system.
(The wavefunction  returned  by  GAUSSIAN-88  in  this  case
corresponds  to  an excited state configuration of Cu#d2#u.)
Since the NBO program communicates  directly  with  the  ESS
program  for  details about the ECP, no special keywords are
necessary.

0 Use of an ECP shows up most directly in the NPA portion of
the output, shown below:
NATURAL POPULATIONS:  Natural atomic orbital occupancies

 NAO Atom #  lang   Type(AO)    Occupancy      Energy  -----
----------------------------------------------------
  1   Cu  1  s      Val( 4s)     0.94240      -0.26321
  2   Cu  1  s      Ryd( 5s)     0.00019       0.92165
  3   Cu  1  px     Ryd( 4p)     0.99604      -0.06989
  4   Cu  1  px     Ryd( 5p)     0.00001       0.09916
  5   Cu  1  py     Ryd( 4p)     0.99604      -0.06989
  6   Cu  1  py     Ryd( 5p)     0.00001       0.09916
  7   Cu  1  pz     Ryd( 5p)     0.05481       1.09062
  8   Cu  1  pz     Ryd( 4p)     0.00062       0.52821
  9   Cu  1  dxy    Val( 3d)     0.00000      -0.36077
 10   Cu  1  dxy    Ryd( 4d)     0.00000       0.72280
 11   Cu  1  dxz    Val( 3d)     1.99997      -1.29316
 12   Cu  1  dxz    Ryd( 4d)     0.00398       0.75681
 13   Cu  1  dyz    Val( 3d)     1.99997      -1.29316
 14   Cu  1  dyz    Ryd( 4d)     0.00398       0.75681
 15   Cu  1  dx2y2  Val( 3d)     1.99939      -1.38791
 16   Cu  1  dx2y2  Ryd( 4d)     0.00061       0.67825
 17   Cu  1  dz2    Val( 3d)     1.99890      -1.26114
 18   Cu  1  dz2    Ryd( 4d)     0.00308       1.16392

 19   Cu  2  s      Val( 4s)     0.94240      -0.26321
 20   Cu  2  s      Ryd( 5s)     0.00019       0.92165
 21   Cu  2  px     Ryd( 4p)     0.99604      -0.06989
 22   Cu  2  px     Ryd( 5p)     0.00001       0.09916
 23   Cu  2  py     Ryd( 4p)     0.99604      -0.06989
 24   Cu  2  py     Ryd( 5p)     0.00001       0.09916
 25   Cu  2  pz     Ryd( 5p)     0.05481       1.09062
 26   Cu  2  pz     Ryd( 4p)     0.00062       0.52821
 27   Cu  2  dxy    Val( 3d)     0.00000      -0.36077
 28   Cu  2  dxy    Ryd( 4d)     0.00000       0.72280
 29   Cu  2  dxz    Val( 3d)     1.99997      -1.29316
 30   Cu  2  dxz    Ryd( 4d)     0.00398       0.75681



                       July 11, 1995





                           - 92 -


31   Cu  2  dyz    Val( 3d)     1.99997      -1.29316
 32   Cu  2  dyz    Ryd( 4d)     0.00398       0.75681
 33   Cu  2  dx2y2  Val( 3d)     1.99939      -1.38791
 34   Cu  2  dx2y2  Ryd( 4d)     0.00061       0.67825
 35   Cu  2  dz2    Val( 3d)     1.99890      -1.26114
 36   Cu  2  dz2    Ryd( 4d)     0.00308       1.16392

[ 36 electrons found in the effective core potential]

WARNING:  Population inversion found on atom Cu 1
          Population inversion found on atom Cu 2


Summary of Natural Population Analysis:

                                      Natural Population
              Natural                              ---------
--------------------------------------
   Atom #      Charge         Core       Valence     Rydberg
Total                                             ----------
-------------------------------------------------------------
    Cu   1     0.00000      18.00000      8.94064    2.05936
29.00000
    Cu  2     0.00000      18.00000      8.94064     2.05936
29.00000
=======================================================================
  *  Total  *   0.00000      36.00000    17.88127    4.11873
58.00000

                                Natural Population  --------
------------------------------------------------
  Effective Core            36.00000
  Valence                   17.88127 ( 81.2785% of  22)
  Natural Minimal Basis     53.88127 ( 92.8987% of  58)
  Natural Rydberg Basis      4.11873 (  7.1013% of  58)  ---
-----------------------------------------------------

   Atom #          Natural Electron Configuration  ---------
-
------------------------------------------------------------------
    Cu  1      [core]4s( 0.94)3d( 8.00)4p( 1.99)4d( 0.01)5p(
0.05)
    Cu  2      [core]4s( 0.94)3d( 8.00)4p( 1.99)4d( 0.01)5p(
0.05)

 #T

     @seg

           #N

          0 As noted below the first NPA table, 36 electrons
          were  found  in the ECP, so the labels for NAOs in
          the table  begin  with  the  designations  4#Is#N,



                       July 11, 1995





                           - 93 -


          5#Is#N,
          etc. of the presumed  extra-core  electrons.   The
          ECP  electrons  are duly entered in the NPA tables
          (labelled as ``effective core'' in the NPA summary
          table)  as  part of the total Lewis occupancy, and
          are taken into proper account in assigning  atomic
          charges.   The  NPA output in this case includes a
          ``population inversion'' message to warn that  one
          or  more NAO occupancies are not ordered in accor-
          dance   with   the   energy   order   [e.g.,   the
          3#Id#N#dxy#u orbital (NAO 9) is unoccupied in this
          excited configuration, although  its  energy  lies
          below    the    occupied    4#Is#N,   4#Ip#N#dy#u,
          4#Ip#N#dz#u levels.]

          0 The main ECP effect in the NBO  portion  of  the
          output  is  the  omission  of core NBOs, as illus-
          trated below:
NATURAL BOND ORBITAL ANALYSIS:

                      Occupancies         Lewis    Structure
Low   High
          Occ.      -------------------    -----------------
occ   occ
 Cycle   Thresh.   Lewis    Non-Lewis      CR   BD   3C   LP
(L)                         (NL)                         Dev
=============================================================================
  1(1)     1.90     57.99970    0.00030       0    3   0   8
0                 0               0.00            ----------
-------------------------------------------------------------------

Structure accepted: No low occupancy Lewis orbitals

--------------------------------------------------------
  Effective Core           36.00000
  Valence Lewis            21.99970 ( 99.999% of  22)
 ==================       ============================
  Total Lewis              57.99970 ( 99.999% of  58)
 -----------------------------------------------------
  Valence non-Lewis         0.00000 (  0.000% of  58)
  Rydberg non-Lewis         0.00030 (  0.001% of  58)
 ==================       ============================
  Total non-Lewis           0.00030 (  0.001% of  58)  -----
---------------------------------------------------


    (Occupancy)   Bond orbital/ Coefficients/ Hybrids  -----
-----
---------------------------------------------------------------------
  1. (2.00000) BD ( 1)Cu 1-Cu 2
               ( 50.00%)   0.7071*Cu  1  s(  94.13%)p  0.06(
5.54%)d 0.00(  0.33%)
                                        0.9702       -0.0003
0.0000  0.0000  0.0000



                       July 11, 1995





                           - 94 -


0.0000 -0.2340  0.0245  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0225
0.0530
               ( 50.00%)   0.7071*Cu  2  s(  94.13%)p  0.06(
5.54%)d 0.00(  0.33%)
                                        0.9702       -0.0003
0.0000  0.0000  0.0000
                                        0.0000        0.2340
-0.0245  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0225
0.0530
  2. (2.00000) BD ( 2)Cu 1-Cu 2
               ( 50.00%)   0.7071*Cu  1  s(   0.00%)p  1.00(
99.60%)d 0.00(  0.40%)
                                        0.0000        0.0000
0.9980  0.0029  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                       -0.0035       -0.0630
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000
               ( 50.00%)   0.7071*Cu  2  s(   0.00%)p  1.00(
99.60%)d 0.00(  0.40%)
                                        0.0000        0.0000
0.9980  0.0029  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0035        0.0630
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000
  3. (2.00000) BD ( 3)Cu 1-Cu 2
               ( 50.00%)   0.7071*Cu  1  s(   0.00%)p  1.00(
99.60%)d 0.00(  0.40%)
                                        0.0000        0.0000
0.0000  0.0000  0.9980
                                        0.0029        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
-0.0035 -0.0630  0.0000
                                        0.0000        0.0000
0.0000
               ( 50.00%)   0.7071*Cu  2  s(   0.00%)p  1.00(
99.60%)d 0.00(  0.40%)
                                        0.0000        0.0000
0.0000  0.0000  0.9980
                                        0.0029        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000



                       July 11, 1995





                           - 95 -


0.0035
0.0630  0.0000
                                        0.0000        0.0000
0.0000
  4. (2.00000) LP ( 1)Cu  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.9998
                                       -0.0175        0.0000
0.0000
  5. (2.00000) LP ( 2)Cu  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0037
                                       -0.0010        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
1.0000  0.0026  0.0000
                                        0.0000        0.0000
0.0000
  6. (2.00000) LP ( 3)Cu  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
                                        0.0000        0.0000
0.0037 -0.0010  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        1.0000        0.0026
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000
  7. (1.99985) LP ( 4)Cu  1              s(   0.06%)p  0.02(
0.00%)d99.99( 99.94%)
                                        0.0231        0.0070
0.0000  0.0000  0.0000
                                        0.0000       -0.0030
-0.0008  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000       -0.9996
-0.0115
  8. (2.00000) LP ( 1)Cu  2              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.9998
                                       -0.0175        0.0000
0.0000



                       July 11, 1995





                           - 96 -


9. (2.00000) LP  (  2)Cu  2              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
                                        0.0000        0.0000
0.0000  0.0000 -0.0037
                                        0.0010        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0000
1.0000  0.0026  0.0000
                                        0.0000        0.0000
0.0000
 10. (2.00000) LP ( 3)Cu  2              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
                                        0.0000        0.0000
-0.0037  0.0010  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        1.0000        0.0026
0.0000  0.0000  0.0000
                                        0.0000        0.0000
0.0000
 11. (1.99985) LP ( 4)Cu  2              s(   0.06%)p  0.02(
0.00%)d99.99( 99.94%)
                                        0.0231        0.0070
0.0000  0.0000  0.0000
                                        0.0000        0.0030
0.0008  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000       -0.9996
-0.0115
 12. (0.00015) RY*( 1)Cu  1              s(  63.84%)p  0.51(
32.31%)d 0.06(  3.85%)
                                       -0.1106        0.7913
0.0000  0.0000  0.0000
                                        0.0000       -0.4699
0.3199  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0064
-0.1962
 13.  (0.00000)  RY*(   2)Cu   1               s(    0.00%)p
1.00(100.00%)d 0.00(  0.00%)
 14.  (0.00000)  RY*(   3)Cu   1               s(    0.00%)p
1.00(100.00%)d 0.00(  0.00%)
 15. (0.00000) RY*( 4)Cu  1              s(  31.12%)p  2.21(
68.87%)d 0.00(  0.00%)
 16. (0.00000) RY*(  5)Cu  1              s(   7.79%)p11.84(
92.21%)d 0.00(  0.00%)
 17. (0.00000) RY*( 6)Cu  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 18. (0.00000) RY*( 7)Cu  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 19. (0.00000) RY*( 8)Cu  1              s(   0.00%)p  1.00(
0.40%)d99.99( 99.60%)



                       July 11, 1995





                           - 97 -


20. (0.00000) RY*(  9)Cu  1              s(   0.00%)p  1.00(
0.40%)d99.99( 99.60%)
 21. (0.00000) RY*(10)Cu  1              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 22. (0.00000) RY*(11)Cu  1              s(   3.06%)p  0.35(
1.07%)d31.35( 95.87%)
 23. (0.00015) RY*( 1)Cu  2              s(  63.84%)p  0.51(
32.31%)d 0.06(  3.85%)
                                       -0.1106        0.7913
0.0000  0.0000  0.0000
                                        0.0000        0.4699
-0.3199  0.0000  0.0000
                                        0.0000        0.0000
0.0000  0.0000  0.0000
                                        0.0000        0.0064
-0.1962
 24.  (0.00000)  RY*(   2)Cu   2               s(    0.00%)p
1.00(100.00%)d 0.00(  0.00%)
 25.  (0.00000)  RY*(   3)Cu   2               s(    0.00%)p
1.00(100.00%)d 0.00(  0.00%)
 26. (0.00000) RY*( 4)Cu  2              s(  31.12%)p  2.21(
68.87%)d 0.00(  0.00%)
 27. (0.00000) RY*(  5)Cu  2              s(   7.79%)p11.84(
92.21%)d 0.00(  0.00%)
 28. (0.00000) RY*( 6)Cu  2              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 29. (0.00000) RY*( 7)Cu  2              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 30. (0.00000) RY*( 8)Cu  2              s(   0.00%)p  1.00(
0.40%)d99.99( 99.60%)
 31. (0.00000) RY*( 9)Cu  2              s(   0.00%)p  1.00(
0.40%)d99.99( 99.60%)
 32. (0.00000) RY*(10)Cu  2              s(   0.00%)p  0.00(
0.00%)d 1.00(100.00%)
 33. (0.00000) RY*(11)Cu  2              s(   3.06%)p  0.35(
1.07%)d31.35( 95.87%)
 34. (0.00000) BD*( 1)Cu 1-Cu 2
               ( 50.00%)   0.7071*Cu  1  s(  94.13%)p  0.06(
5.54%)d 0.00(  0.33%)
               ( 50.00%)  -0.7071*Cu  2  s(  94.13%)p  0.06(
5.54%)d 0.00(  0.33%)
 35. (0.00000) BD*( 2)Cu 1-Cu 2
               ( 50.00%)   0.7071*Cu  1  s(   0.00%)p  1.00(
99.60%)d 0.00(  0.40%)
               ( 50.00%)  -0.7071*Cu  2  s(   0.00%)p  1.00(
99.60%)d 0.00(  0.40%)
 36. (0.00000) BD*( 3)Cu 1-Cu 2
               ( 50.00%)   0.7071*Cu  1  s(   0.00%)p  1.00(
99.60%)d 0.00(  0.40%)
               ( 50.00%)  -0.7071*Cu  2  s(   0.00%)p  1.00(
99.60%)d 0.00(  0.40%)






                       July 11, 1995





                           - 98 -


Natural Bond Orbitals (Summary):

                                                    Princi-
pal Delocalizations
          NBO                     Occupancy           Energy
(geminal,vicinal,remote)
===============================================================================
Molecular unit  1  (Cu2)
  1. BD ( 1)Cu 1-Cu 2       2.00000    -0.53276
  2. BD ( 2)Cu 1-Cu 2       2.00000    -0.21503
  3. BD ( 3)Cu 1-Cu 2       2.00000    -0.21503
  4. LP ( 1)Cu 1            2.00000    -1.38854
  5. LP ( 2)Cu 1            2.00000    -1.29317
  6. LP ( 3)Cu 1            2.00000    -1.29317
  7. LP ( 4)Cu 1            1.99985    -1.26133
  8. LP ( 1)Cu 2            2.00000    -1.38854
  9. LP ( 2)Cu 2            2.00000    -1.29317
 10. LP ( 3)Cu 2            2.00000    -1.29317
 11. LP ( 4)Cu 2            1.99985    -1.26133
 12. RY*( 1)Cu 1            0.00015     0.70166
 13. RY*( 2)Cu 1            0.00000     0.09932
 14. RY*( 3)Cu 1            0.00000     0.09932
 15. RY*( 4)Cu 1            0.00000     1.09217
 16. RY*( 5)Cu 1            0.00000     0.44430
 17. RY*( 6)Cu 1            0.00000    -0.36077
 18. RY*( 7)Cu 1            0.00000     0.72280
 19. RY*( 8)Cu 1            0.00000     0.75266
 20. RY*( 9)Cu 1            0.00000     0.75266
 21. RY*(10)Cu 1            0.00000     0.67888
 22. RY*(11)Cu 1            0.00000     1.26372
 23. RY*( 1)Cu 2            0.00015     0.70166
 24. RY*( 2)Cu 2            0.00000     0.09932
 25. RY*( 3)Cu 2            0.00000     0.09932
 26. RY*( 4)Cu 2            0.00000     1.09217
 27. RY*( 5)Cu 2            0.00000     0.44430
 28. RY*( 6)Cu 2            0.00000    -0.36077
 29. RY*( 7)Cu 2            0.00000     0.72280
 30. RY*( 8)Cu 2            0.00000     0.75266
 31. RY*( 9)Cu 2            0.00000     0.75266
 32. RY*(10)Cu 2            0.00000     0.67888
 33. RY*(11)Cu 2            0.00000     1.26372
 34. BD*( 1)Cu 1-Cu 2       0.00000     0.41179
 35. BD*( 2)Cu 1-Cu 2       0.00000     0.08327
 36. BD*( 3)Cu 1-Cu 2       0.00000     0.08327
      -------------------------------
             Total Lewis   57.99970  ( 99.9995%)
       Valence non-Lewis    0.00000  (  0.0000%)
       Rydberg non-Lewis    0.00030  (  0.0005%)
      -------------------------------
           Total unit  1   58.00000  (100.0000%)
          Charge unit  1    0.00000

 #T




                       July 11, 1995





                           - 99 -


@seg

 #N

0 As the output shows, the NBO tables include  reference  to
only  11 occupied NBOs, rather than the 29 that would appear
in a full calculation.  Semi-empirical methods that  neglect
core electrons (AMPAC, etc.) are handled similarly.

0 The output for the Cu#d2#u example also  illustrates  some
aspects of the inclusion of #Id#N orbitals in the basis set.
NBOs 4-7 and 8-11 represent  the  3#Id#N#u8#d  subshells  on
each  atom,  essentially  of  pure  atomic  #Id#N  character
(except for a small admixture of #Ip#N character in NBOs  7,
11).   Both  the  gma  #dCuCu#u  bond  (NBO 1) and the two i
#dCuCu#u bonds (NBOs 2, 3) have very  slight  admixtures  (<
0.4%) of #Id#N character.  The remaining orbitals of predom-
inant #Id#N character (NBOs 17-22 and 28-33) are of negligi-
ble  occupancy.   Note that the abbreviated ``#Isp#u #dd#umu
#d#N'' designations can lead  to  strange  variations  among
hybrids  of  essentially  similar  character;  thus,  NBO 20
(#Ip#u1.0#dd#u99.9#d#N), NBO 21 (#Id#N#u1.0#d), and  NBO  22
(#Is#u3.1#dp#u0.4#dd#u31.4#d#N)  are  all  of nearly pure (>
95%) #Id#N character, the difference in  labelling  stemming
from  whether  there  is sufficient #Is#N or #Ip#N character
(in numerical terms) to express the hybrid ratios in  #Isp#u
#dd#umu  #d#N  form.   Consult  the  percentages  of #Is#N-.
#Ip#N-, and #Id#N-character whenever there  is  doubt  about
how  to  interpret a particular #Isp#u #dd#umu #d#N designa-
tion.
#BB.7   FILE47:  INPUT  FOR  THE  GENNBO   STAND-ALONE   NBO
PROGRAM#N

#IB.7.1  Introduction#N

0 The general NBO program, GENNBO, is a stand-alone  program
which  is  not directly attached to an ESS program.  Rather,
information about the wavefunction is provided to  the  core
NBO  routines  by a sequential input file, FILE47, described
in this section.

0 Some knowledge of FILE47 is useful even if your  NBO  pro-
gram  is  attached to an ESS package.  If requested (see the
ARCHIVE option, Section B.2.5), the NBO program  writes  out
FILE47  which  summarizes  all information pertaining to the
computed electronic wavefunction.  This file can  be  subse-
quently  used  as input to the GENNBO program (reassigned as
LFN 5) to repeat the analysis of this  wavefunction;  simply
include  the $NBO, $CORE, and $CHOOSE keylists in FILE47 and
execute GENNBO.  You need never recompute  the  wavefunction
to  vary  its  NBO analysis!  In fact, generating the FILE47
input file is a useful way to  archive  a  wavefunction  for
future  use or reference.  [Note: the GENNBO program can not
perform the NBO energetic analysis ($DEL keylist) since this



                       July 11, 1995





                          - 100 -


would
require  access  to  the  formatted  one-  and  two-electron
integrals of the parent ESS package.]

0 If you intend to use the NBO program in  conjunction  with
an  ESS package not supported in this distribution (i.e. for
which no custom drivers are provided),  you  might  consider
attaching  a  routine  to your ESS program which would write
the proper form of FILE47 for input into the GENNBO program.
Thus, a two-step process would be required to obtain the NBO
analysis of a wavefunction: (i) the initial  calculation  of
the  wavefunction with the ESS package, writing FILE47; (ii)
the NBO analysis using the GENNBO  program  with  FILE47  as
input.  Alternatively, you may decide to attach the NBO pro-
gram directly to your ESS package by writing your own driver
routines.   See  the  Programmer's  Guide, Section C.13, for
direction.

0 Section B.7.2 describes and illustrates the overall format
of  FILE47.   Sections B.7.3-B.7.7 detail the entries of the
keylists and datalists  that  compose  this  file.   #IB.7.2
Format of the FILE47 Input File#N

0 The FILE47 input file is composed of a set of keylists and
datalists, each list beginning with a ``$'' identifier (e.g.
``$BASIS'') and ending with ``$END'',

#T     $BASIS   entries  $END#N

Individual lists are used to specify basis  set  information
($BASIS),  density matrix elements ($DENSITY), and so forth.
The order of the lists within FILE47 is immaterial.  Entries
within  each  datalist are generally free format, and may be
continued on as many lines as desired.  An exclamation point
(!)  on  any line terminates input from the line, and may be
followed by arbitrary comments.  The $GENNBO keylist and the
$COORD,   $BASIS,   $DENSITY,  and  $OVERLAP  datalists  are
required, but the other  datalists  ($FOCK,  $LCAOMO,  $CON-
TRACT,  $DIPOLE)  or the standard NBO keylists ($NBO, $CORE,
$CHOOSE) are optional, depending on the  requested  applica-
tion.   If  the  $NBO  keylist is not present in FILE47, the
default NBO analysis is performed.

0 The entries of each keylist or datalist may  be  keywords,
numerical matrix elements, or other parameters of prescribed
form.   A  sample  FILE47  input  file  (for  the  RHF/3-21G
methyl#|amine example of Section A.3) is shown below:
 $GENNBO  NATOMS=7  NBAS=28  UPPER  BODM $END
 $NBO  NAOMO=PVAL  $END
 $COORD
 Methylamine...Pople-Gordon standard geometry...RHF/3-21G
  6   6   -0.74464  -0.03926   0.00000    ! Carbon
  7   7    0.71885   0.09893   0.00000    ! Nitrogen
  1   1   -1.00976  -1.09653   0.00000    ! Hydrogen



                       July 11, 1995





                          - 101 -


1   1   -1.15467   0.43814   0.88998    ! Hydrogen
  1   1   -1.15467   0.43814  -0.88998    ! Hydrogen
  1   1    1.09878  -0.34343  -0.82466    ! Hydrogen
  1   1    1.09878  -0.34343   0.82466    ! Hydrogen
 $END
 $BASIS
   CENTER                                                  =
1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,3,3,4,4,5,5,6,6,7,7
    LABEL                                                  =
1,1,101,102,103,1,101,102,103,1,1,101,102,103,1,101,102,103,
            1,1,1,1,1,1,1,1,1,1
 $END
 $CONTRACT
  NSHELL =  16
    NEXP =  21
   NCOMP =   1,  4,  4,  1,  4,  4,  1,  1,  1,  1,  1,   1,
1,  1,  1,  1
   NPRIM =   3,  2,  1,  3,  2,  1,  2,  1,  2,  1,  2,   1,
2,  1,  2,  1
    NPTR =   1,  4,  6,  7, 10, 12, 13, 15, 16, 18, 16,  18,
19, 21, 19, 21
     EXP =   0.1722560E+03,  0.2591090E+02,   0.5533350E+01,
0.3664980E+01,
             0.7705450E+00,  0.1958570E+00,   0.2427660E+03,
0.3648510E+02,
             0.7814490E+01,  0.5425220E+01,   0.1149150E+01,
0.2832050E+00,
             0.5447178E+01,  0.8245472E+00,   0.1831916E+00,
0.5447178E+01,
             0.8245472E+00,  0.1831916E+00,   0.5447178E+01,
0.8245472E+00,
             0.1831916E+00
      CS =   0.2093132E+01,  0.2936751E+01,   0.1801737E+01,
-0.7473843E+00,
             0.7126610E+00,  0.2098285E+00,   0.2624092E+01,
0.3734359E+01,
             0.2353454E+01, -0.1047101E+01,   0.9685501E+00,
0.2766851E+00,
             0.3971513E+00,  0.5579200E+00,   0.1995672E+00,
0.3971513E+00,
             0.5579200E+00,  0.1995672E+00,   0.3971513E+00,
0.5579200E+00,
             0.1995672E+00
      CP =   0.0000000E+00,  0.0000000E+00,   0.0000000E+00,
0.1709178E+01,
             0.8856221E+00,  0.1857223E+00,   0.0000000E+00,
0.0000000E+00,
             0.0000000E+00,  0.2808586E+01,   0.1456735E+01,
0.2944871E+00,
             0.0000000E+00,  0.0000000E+00,   0.0000000E+00,
0.0000000E+00,
             0.0000000E+00,  0.0000000E+00,   0.0000000E+00,
0.0000000E+00,
             0.0000000E+00



                       July 11, 1995





                          - 102 -


$END
 $OVERLAP   ! Overlap matrix elements in the AO basis
  0.10000000E+01  0.19144744E+00  0.10000000E+01  . . .
 $END
 $DENSITY   ! Bond-order matrix elements in the AO basis
  0.20363224E+01  0.11085239E+00  0.10393086E+00  . . .
 $END
 $FOCK      ! Fock matrix elements in the AO basis
 -0.11127777E+02 -0.28589754E+01 -0.89570272E+00  . . .
 $END
 $LCAOMO    ! AO to MO transformation matrix
 -0.57428375E-03 -0.23835711E-02  0.17741799E-02  . . .
 $END
 $DIPOLE    ! dipole matrix elements in the AO basis
 -0.14071733E+01 -0.26939974E+00 -0.14071733E+01  . . .
 $END
 #T

@seg

 #N

The nine lists of FILE47 are described in turn in  the  fol-
lowing  sections,  making  use of this example for illustra-
tion.  #IB.7.3 $GENNBO Keylist#N

0 The $GENNBO keylist (required) contains keywords essential
to  the  proper execution of the NBO program.  The following
is the list of keywords recognized by this keylist:

#IOPTION DESCRIPTION#N


Instructs GENNBO to reuse an  old  NBO  direct-access  file,
FILE48,  rather  than create a new FILE48 from the wavefunc-
tion  information  contained  in  the  FILE47   data#|lists.
Therefore,   if   the   REUSE   keyword  is  specified,  all
data#|lists in FILE47 will be ignored, but the $NBO,  $CORE,
and $CHOOSE keylists will still be recognized.  This keyword
preempts all other keywords of the $GENNBO keylist.

Number of atoms in the molecule (required).

Number of basis functions (required).

Designates an open shell wavefunction.  GENNBO  will  subse-
quently read in alpha and beta density, Fock, and MO coeffi-
cient matrices.

Indicates that the AO basis set is orthogonal  (basis  func-
tions  are  always  assumed normalized).  If this keyword is
specified, GENNBO will not read the $OVERLAP datalist.  This
keyword   is  incompatible  with  $NBO  keywords  for  `pre-
orthogonal' basis sets (SPNAO, SPNHO, SPNBO, SPNLMO, AOPNAO,



                       July 11, 1995





                          - 103 -


AOPNHO,
AOPNBO, AOPNLMO).

Indicates that only the upper  triangular  portions  of  the
overlap,  density,  Fock,  and dipole matrices are listed in
the their respective datalists.  By default, GENNBO  assumes
that the full matrices are given.

Indicates that the $DENSITY datalist contains the bond-order
matrix  (``Fock-Dirac density matrix'') rather than the den-
sity matrix (i.e., matrix elements of the density operator).
(In orthogonal AO basis sets, the bond-order matrix and den-
sity matrix are identical, but in nonorthogonal  basis  sets
they  must  be  distinguished.)   By default, GENNBO assumes
this data#|list contains the density  matrix  elements.   If
``BODM''  is included, the datalist elements are transformed
with the AO overlap  matrix  to  produce  the  true  density
matrix.

Indicates that  the  atomic  coordinates  ($COORD)  and  the
dipole  integrals ($DIPOLE) are in atomic units, rather than
the default angstroms.

Indicates that the Fock matrix elements ($FOCK)  have  units
of electron volts (eV), rather than the default atomic units
(Hartrees).

Instructs GENNBO to use the set of  seven  cubic  #If#N-type
functions  rather than the ten Cartesian or seven pure #If#N
functions (cf. Section B.7.5).



The methylamine sample $GENNBO keylist specifies 7 atoms, 28
basis functions, upper triangular matrix input, and $DENSITY
datalist containing the bond-order matrix.   #IB.7.4  $COORD
Datalist#N

0 The $COORD datalist (required, unless REUSE  is  specified
in  $GENNBO) contains the job title and information indicat-
ing the identity and coordinates  of  each  atom,  including
missing core electrons or effective core potentials.

0 The first line following the $COORD identifier is an arbi-
trary job title, up to 80 characters.

0 Subsequent lines are used to specify  the  atomic  number,
the  nuclear  charge,  and  the  (x,y,z) coordinates of each
atom.  [For example, atom 1 in the methylamine sample  input
is a carbon atom (atomic number 6) with nuclear charge 6 and
coordinates x = minus  0.74464,  y  =  minus  0.03926,  z  =
0.00000,  in  angstroms.]  Coordinates  are assumed to be in
angstroms unless the BOHR keyword  appears  in  the  $GENNBO
keylist,  specifying  atomic  units.   The atomic number and



                       July 11, 1995





                          - 104 -


nuclear
charge are generally identical, but if  core  electrons  are
neglected  (as  in  most  semi-empirical  treatments)  or if
effective core potentials (ECP) are  employed,  the  nuclear
charge  will be less than the atomic number by the number of
electrons neglected on that particular atom.  Thus,  for  an
AMPAC  calculation, in which the two 1#Is#N core electron of
a carbon atom are neglected,  the  line  following  the  job
title in the methylamine example would read

#T   6    4    -0.74464   -0.03926    0.00000   ! Carbon#N

where ``4'' is the effective (valence) nuclear charge of the
atom.  #IB.7.5 $BASIS Datalist#N

0 The $BASIS datalist (required, unless REUSE  is  specified
in  $GENNBO)  provides  essential  information  about the AO
basis functions, specifying the atomic center and the  angu-
lar            symmetry            (           ,           x
,
y                             ,                            z
, etc.) of each AO.  This information is  contained  in  two
arrays in this datalist called CENTER and LABEL.

0 The atomic center for each AO  is  specified  by  entering
``CENTER=''  followed  by  the serial number of the atom for
each AO, separated by commas or spaces.  [For  example,  the
entry

#T                          CENTER                         =
1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,3,3,4,4,5,5,6,6,7,7#N

of the methylamine sample file indicates that  the  first  9
AOs (1-9) are centered on atom 1 (the carbon atom), the next
nine AOs (10-18) on center 2, and so forth.]

0 The angular symmetry for each AO is specified by  entering
``LABEL=''  followed  by  a  symmetry  label  for  each  AO,
separated by commas or  spaces.   The  NBO  program  handles
#Is#N,  #Ip#N,  #Id#N, or #If#N (= 0-3) basis AOs, of either
cartesian or pure angular symmetry  types.   The  label  for
each  AO  is  a 3-digit integer of the form + #Ik#N + #Im#N,
where #Ik#N is 0 (cartesian) or 50 (pure), and  #Im#N  is  a
particular component of the symmetry (see table below).  For
#Is#N or #Ip#N AOs, the cartesian and pure sets are  identi-
cal,  so  each  AO can be labelled in two distinct ways, but
the six cartesian #Id#N functions can be transformed to  the
five pure #Id#N functions plus an additional #Is#N function,
and the ten cartesian #If#N functions can be transformed  to
the  seven  pure #If#N functions plus three additional #Ip#N
functions.  Two distinct sets of pure  #If#N  functions  are
recognized, the ``standard'' [default] set and the ``cubic''
set, the latter being used whenever the  ``CUBICF''  keyword
is included in the $GENNBO keylist.



                       July 11, 1995





                          - 105 -


0 The labels associated with each allowed AO  function  type
are  tabulated  below, where #Ix, y, z#N refer to the speci-
fied cartesian axis system:

#_Pure    #If#N    ``cubic''    set:#/>>     351//#If#N(D1):
x(5x#u2#dminus   3r#u2#d)>>  352//#If#N(D2):  y(5y#u2#dminus
3r#u2#d)>>   353//#If#N(D3):    z(5z#u2#dminus    3r#u2#d)>>
354//#If#N(B):     xyz>>    355//#If#N(E1):    x(z#u2#dminus
y#u2#d)>>    356//#If#N(E2):     y(z#u2#dminus     x#u2#d)>>
357//#If#N(E3):   z(x#u2#dminus   y#u2#d)>>  356//#If#N(c3):
x(x#u2#dminus  3y#u2#d)>>   357//#If#N(s3):   y(3x#u2#dminus
y#u2#d)>>

[For example, in the methylamine  sample  input,  the  first
nine entries of the LABEL array,

#T    LABEL = 1,1,101,102,103,1,101,102,103,. . .#N

identify the first 9 AOs (of carbon) as being  of   ,   ,  x
,                                                          y
,                                                          z
,
 ,                                                         x
,                                                          y
,                                                          z
type, respectively.] #IB.7.6 $CONTRACT Datalist#N

0 The  $CONTRACT  datalist  (optional)  contains  additional
information  about  the contraction coefficients and orbital
exponents of AO basis functions.  This  information  is  not
used in the NBO analysis of a wavefunction.  However, if the
AOINFO or PLOT keyword is specified in the $NBO keylist (See
Section  B.2.5),  the  GENNBO driver routines write out this
information to an external file (LFN 31) in the proper  for-
mat for orbital plotting with the ORBPLOT program.  Omit the
$CONTRACT datalist if you do  not  intend  to  make  orbital
plots.

0 Two integers must be initially given: NSHELL  (the  number
of  shells of basis functions) and NEXP (the number of orbi-
tal exponents).  [In the methylamine example, there  are  16
shells  of basis functions and 27 orbital exponents.]  These
integers should precede  the  remainder  of  the  basis  set
information of this datalist.

0 The number of components (basis functions) in  each  shell
is  specified in the NCOMP array.  The sum of the components
for each shell should equal the total number of basis  func-
tions.   This  list  of  components is a partitioning of the
basis function centers and labels (in the  $BASIS  datalist)
into  shells.   [For example, in the methylamine sample, the
NCOMP array

#T    NCOMP = 1,4,4,. . .#N



                       July 11, 1995





                          - 106 -


indicates that the first three shells  have  a  total  of  9
(i.e.  1+4+4)  basis  functions.   These are the 9 AOs (1-9)
discussed previously in the $BASIS datalist.]

0 The NPRIM array gives the  number  of  primitive  gaussian
functions  of each shell.  [For the methylamine example, the
first three shells of the AO basis are contractions of

#T    NPRIM = 3,2,1,. . .#N

three, two, and one primitives, respectively,  corresponding
to the conventional ``3-21G'' basis set designation.]

0 Pointers for each shell are  listed  in  the  NPTR  array.
These pointers specify the location of the orbital exponents
(EXP) and contraction coefficients (CS, CP, CD, CF) for each
shell.  [In the sample input file,

#T     NPTR = 1,4,6,. . .#N

the orbital exponents and contraction coefficients  for  the
first  three  shells  begin at elements 1, 4, and 6, respec-
tively.]

0 EXP, CS, CP, CD, and CF are free format, real arrays  con-
taining  the  orbital exponents, and the s, p, d, and f con-
traction coefficients of the AO basis  set.   NEXP  elements
should  appear  in each array, and the arrays of contraction
coefficients need only appear if there are  basis  functions
of that particular symmetry in the basis set.  [For example,
the 3-21G basis of the sample  methylamine  input  only  has
#Is#N  and  #Ip#N basis functions.  Therefore, the CD and CF
arrays are not necessary.]

0 The information in the $CONTRACT datalist along with  that
in the $BASIS datalist is enough to completely determine the
AO basis set.  [For example, the second shell on the  methy-
lamine  sample contains 4 basis functions (NCOMP). These are
#Is#N,  #Ip#N#dx#u,  #Ip#N#dy#u,  and  #Ip#N#dz#u   orbitals
(LABEL),  all  centered  on  atom 1 (CENTER), and each basis
function  is  a  contraction  of  two  primitive   gaussians
(NPRIM).   From  NPTR, EXP, CS, and CP, we find the explicit
form of these functions:

hi #ds#u(#Br#N)   hsp =      hsp +

hi            #dp#dx#u#u(#Br#N)             =              1
+                                                          2

hi            #dp#dy#u#u(#Br#N)             =              3
+                                                          4

hi            #dp#dz#u#u(#Br#N)             =              5
+                                                          6



                       July 11, 1995





                          - 107 -


where  #Br#N=(x,y,z)  is  measured in bohr units relative to
the  cartesian  coordinates  of  atom  1.]  #IB.7.7   Matrix
Datalists#N

0  The  remaining  datalists  ($OVERLAP,  $DENSITY,   $FOCK,
$LCAOMO,  $DIPOLE)  specify various matrix elements possibly
used by the NBO analysis.  All entries  in  these  datalists
are free format, with entries separated by commas or spaces.
Only the upper triangular portions of each symmetric  matrix
(overlap,  density,  Fock, dipole) should be provided if the
UPPER keyword is specified  in  the  $GENNBO  keylist.   The
numbering  of the matrix rows and columns must correspond to
the ordering of the AOs in the $BASIS datalist.   All  three
matrices  of  dipole  integrals should appear in the $DIPOLE
datalist, all #Ix#N integrals before #Iy#N before #Iz#N.

0 Of the matrix datalists, the $DENSITY datalist  is  always
required,  and  the  $OVERLAP data#|list is required for all
non-orthogonal AO basis  sets,  but  other  data#|lists  are
optional  (unless  implicitly  required by specified keyword
options).  Nevertheless, it is good practice to  include  as
many  of these datalists in FILE47 as possible for later use
with keyword options  which  require  them.   The  following
table  lists the $NBO keywords that require each datalist to
be included in FILE47:

#I$NBO Keywords Requiring the Datalist#N

SAO, SPNAO, SPNHO, SPNBO, SPNLMO,  AOPNAO,  AOPNHO,  AOPNBO,
AOPNLMO

E2PERT, FAO, FNAO, FNHO, FNBO, FNLMO

AOMO, NAOMO, NHOMO, NBOMO, NLMOMO

DIAO, DINAO, DINHO, DINBO, DINLMO, DIPOLE

AOINFO, PLOT


0 For example, in the methylamine sample input, the  keyword
``NAOMO=PVAL'' of the $NBO keylist requires that the $LCAOMO
data#|list be present (in addition to  the  $OVERLAP,  $DEN-
SITY,   and  $FOCK  data#|lists  used  for  default  PRINT=2
analysis), but the $DIPOLE data#|list might have been  omit-
ted  in  this case.  Inclusion of the $LCAOMO data#|list (in
addition to the $FOCK datalist) insures that degenerate  MOs
will  be  chosen  in  a  prescribed way for decomposition in
terms of other functions.








                       July 11, 1995





                          - 108 -


#HSection C: NBO PROGRAMMER'S GUIDE#N


#BC.1 INTRODUCTION#N

0 Section  C  constitutes  the  programmer's  guide  to  the
NBO.SRC  program.   It  assumes that the user has a thorough
familiarity with Fortran programming and the  operations  of
the NBO program (Sections A and B) as well as some familiar-
ity with published algorithms  for  NAO/NBO/NLMO  determina-
tion.   This  section  is intended for the accomplished pro-
grammer who wishes to inquire into the details  of  the  NBO
numerical  methods and find the specific source code associ-
ated with individual steps  of  the  published  NAO/NBO/NLMO
algorithms or segments of NBO output.

0 The NBO.SRC program consists  of  about  20000  lines,  of
which  more  than  6000 are comment lines (approximately the
length of this manual!).  These comment  statements  provide
the principal documentation of the steps within each subrou-
tine or function, and should be consulted on questions  per-
taining to individual subprograms.

0 In this Programmer's Guide, we focus on global aspects  of
program organization and data structure.  Individual subpro-
grams (about 180 in number) are described in  capsule  form,
in  the order in which they appear in the source listing, to
indicate the relationship to program tasks and the  associa-
tion  with  specific  segments  of  NBO output.  The capsule
descriptions include  mention  [in  brackets]  of  numerical
thresholds  or  possible  dependencies  on machine precision
that  are  of  particular   concern   to   the   programmer.
Throughout  the  Programmer's Guide, in referring to indivi-
dual subprograms, we use the abbreviation ``SR'' for  ``sub-
routine'' and ``FN'' for ``function''.

0 Sections C.2-C.4 describe the overall NBO.SRC source  lay-
out,  labelled  COMMON blocks, and I/O structures (including
the FILE48 direct access file).  Sections C.5-C.11 then fol-
low  the layout of the source code in describing the princi-
pal groupings of subprograms, with a  brief  description  of
each  subprogram.   Section C.12 similarly describes subpro-
grams of the GENNBO stand-alone program.  The final  section
C.13 provides guidance on attaching the NBO program to a new
ESS package not supported by this distribution.

#BC.2 OVERVIEW OF NBO SOURCE PROGRAM GROUPS#N

0 The NBO.SRC program  is  organized  into  seven  principal
groups  of routines (I-VII), described in Sections C.5-C.11,
respectively, as shown below:






                       July 11, 1995





                          - 109 -


The routines of Groups I, II are  associated  with  the  two
main  tasks  of the NBO program: (1) NAO/NBO/NLMO formation,
and (2) NBO energetic analysis.  Group II routines generally
require  Fock matrix information, and thus are restricted to
RHF and UHF wavefunctions, whereas Group I are applicable to
general  wavefunctions.   Each of these groups is controlled
by a master subroutine (NBO  and  NBOEAN,  respectively)  of
highest  precedence,  which in turn calls routines of secon-
dary precedence (such as NAODRV, NBODRV,  etc.)  to  control
the  task.   Routines are generally clustered together under
the subroutine of next higher precedence,  and  within  each
cluster,  the order of routines generally corresponds to the
chronological sequence in which the routines are  called  in
execution.

0 The remaining Groups III-VI `serve'  various  routines  of
Groups  I-II,  and  are ordered more loosely by function, or
alphabetically.  Groups I-VI are system-independent, whereas
Group  VII  contains  the  special  drivers (RUNNBO, FEAOIN,
DELSCF) for individual ESS programs, whose generic  function
is  described  in  Section C.11.  Further information on the
ESS-specific forms of the Group VII driver routines is given
in the Appendix.

0 A general overview of the subprograms of Groups I  and  II
is shown in the accompanying flow chart, indicating the log-
ical relationship of the routines to be  discussed  in  Sec-
tions C.5, C.6.  The sequence of execution is generally from
top to bottom and from left to right,  with  subprograms  of
equal precedence shown at an equal vertical level.




#HNBO Flow Chart for Group I, II Subprograms#N
|<<3//10//80//+2//+42>>|7______________________99______________________ #T


|< 99, since  this  would  result  in  format
overflows in orbital labels throughout the output.

All entries of a given COMMON block  are  generally  of  the
same  numeric  type  (INTEGER,  LOGICAL, etc.), as specified
below.  The names (dummy), and meaning of variables in  each
primary  COMMON  block  1-6  are  described briefly, with an
asterisk (*) marking the items that must be passed from  the
external ESS program via driver routines:



The INTEGER variables of this block store  general  informa-
tion  related  to  basis  set dimensionality, spin manifold,
number of atoms, and energy units:




The LOGICAL variables  of  this  block  are  set  .TRUE.  or
.FALSE.   depending  on  whether  the ``condition'' (type of
wavefunction, spin set, etc.) is satisfied:


Note (Section B.6.11) that both lpha  and77778 t99a999999  s99p99i99n9999 d77778nsity matrices
should  be  available  if OPEN is set `.TRUE.' for the open-
shell case.





The INTEGER variables (flags) of this  block  are  used  for
storing the keyword options selected by the user in the $NBO
keylist.  In many  cases,  a  variable  of  the  form  IWOPT
(``IW''  stands for ``I Want'') is set to one or zero (or to
some Hollerith content; see below) depending on whether  the
``requested  option''  has been specified or not.  The table
also lists the keyword (if any) that requests the option:


The keyword associated  with  each  element  I=1-54  of  the
JPRINT array is shown below (55-60 are not currently used):


In general, if the flag is set to zero, its associated  key-
word  option  has not been specified.  However, if an option
is requested, its flag can be set to a variety of  positive,
negative,  or  Hollerith values, depending on the parameters
specified with  the  keyword  option.   In  particular,  the
option  flags  associated  with  the matrix output keywords,
described in Section B.2.4, are set according to the follow-
ing scheme:



                       July 11, 1995





                          - 112 -


The INTEGER arrays of this block store  information  on  the
atomic centers and angular symmetry of each AO:





The INTEGER arrays of this block store information about the
orbitals on each atomic center:





The INTEGER variables of this block are the  stored  default
logical  file  numbers  for I/O operations.  The table below
identifies the value (default file assignment) and the  con-
tents  of  the  file  associated  with each LFN (cf. Section
B.2.4):



The remaining `secondary' COMMON blocks 7-18  contain  vari-
ables that remain wholly within the system-independent code,
and thus can be ignored with respect to interfacing to a new
ESS.  Blocks 7-13 involve communication with the Group I, II
subprograms, whereas blocks  14-18  are  wholly  within  the
`support' routines of Groups III-VII.



The INTEGER arrays of this block generally store information
about  the  atomic, bond, and molecular units with which the
NBOs or NAOs are associated.  The meaning of all entries  in
COMMON/NBBAS/  #Ichanges#N  between the NAO and NBO segments
of  the  program,  so  this  block  functions  virtually  as
`scratch  storage,'  and its entries must be approached with
extreme caution!  The following table indicates the  meaning
of COMMON/NBBAS/ entries during NBO segments (only!):




The DOUBLE PRECISION  variables  of  this  block  store  the
default values of various numerical thresh#|olds that can be
set by the user:




The INTEGER variables of this  block  store  the  number  of
orbitals  associated  with  the  ``LEW''  and  ``VAL'' print
parameters (Section B.2.4) and the  10  Hollerith  fragments
required  to  compose  each  of  the  4  possible  types  of



                       July 11, 1995





                          - 113 -


localized
orbital labels (AO, NAO, NHO, NBO):




The INTEGER arrays of this block store information  pertain-
ing to the labelling of NAOs in the NPA output:




The INTEGER scalars, vectors, and arrays of this block store
information pertaining to ``molecular units'':




The INTEGER variables of  this  block  contain  atom  search
lists to direct the search for NBOs and information pertain-
ing to the `topology' (bond connectivity) of the molecule:




The DOUBLE PRECISION variables of this block store  informa-
tion  pertaining  to  the molecular dipole moment and charge
distribution:





The INTEGER variables of this block store  general  informa-
tion  related  to the `card image' (line) being processed by
the free-format input routines:





The  LOGICAL  variables  of  this  block  store  information
related  to  the  current line being read by the free-format
input routines.  In each case, the variable is set .TRUE. if
the specified condition is met:





The  INTEGER  variables  of  this  block  store  information
related to the NBO direct access file (FILE48).  The PARAME-
TER statement
 #T



                       July 11, 1995





                          - 114 -


PARAMETER (NBDAR = 100)

#Nsets the maximum number of logical records  accessible  in
FILE48:





The INTEGER variables of this block provide scratch  storage
for  writing  to  the  NBO direct access file (FILE48).  The
PARAMETER statement
 #T
     PARAMETER (ISINGL = 2, LENGTH = 256)

#Nsets the FILE48 physical record LENGTH  to  256  longwords
(1024 bytes):





The  LOGICAL  variables  of  this  block  store  information
related  to  running the GENNBO program in stand-alone mode.
In each case, the variable is set .TRUE.  if  the  specified
condition is met:



#BC.4 DIRECT ACCESS FILE AND OTHER I/O#N

0 The principal I/O routines of Groups III-V  are  described
in  Sections  C.7-C.9.  The #Iinput#N to the NBO programs is
primarily from the standard ESS input file (LFN 5), and  the
#Ioutput#N is primarily to the standard ESS output file (LFN
6).  Other ``matrix output'' (read/write) I/O is by  default
assigned to LFNs 31-49 (see Table of Section B.2.4), or to a
user-selectable LFN, based on keyword entries  in  the  $NBO
keylist.

0 The remaining two files  that  are  routinely  created  or
modified  by  the  NBO programs are the FILE48 direct access
file (LFN  48)  and  the  FILE47  `archive'  file  (LFN  47,
described  in  Section B.7).  The latter file can also serve
as the main input file (reassigned as LFN 5)  when  the  NBO
program is run in stand-alone GENNBO mode.

0 From the programmer's viewpoint, the most important infor-
mation concerns the organization of the FILE48 direct access
file.  The records of this file are assigned as shown in the
following table.  The items marked with an asterisk (*) must
be provided from the ESS program (e.g., through  the  FEAOIN
driver),  and hence are of particular importance to the pro-
grammer:



                       July 11, 1995





                          - 115 -


[Cartesian  coordinates  (record  9)  and  dipole  integrals
(records 50-52) should be in angstrom units.]

0 The direct access file serves as  a  principal  medium  of
communication  between  all  segments  of  the  NBO program.
Input received  from  the  ESS  program  (Section  C.11)  is
immediately saved in the direct access file and subsequently
fetched by other subprograms, using the fetch/save I/O  rou-
tines  of Section C.7.  Further information on the structure
of the direct access file is specified in COMMON blocks  16,
17 of Section C.3.


#BC.5 NAO/NBO/NLMO ROUTINES (GROUP I)#N

#IC.5.1 SR NBO Master Subroutine#N

0 The subroutine of highest precedence in the core NBO  pro-
gram  is  SR  NBO.  This routine initially requests that the
input file be searched for the  $NBO  keylist  (See  NBOINP,
Section  C.9).   If found, SR NBO continues by calling three
main clusters of programs, as shown below:

|<<3//27//63//+1//+5>>|7_____________________99_____________________               |<<3//10//30//+8//+14>>|7______________________99______________________
|<<3//35//55//+8//+14>>|7______________________99______________________ |<<3//60//80//+8//+14>>|7______________________99______________________


#TV+30                    SR NBO(CORE,MEMORY,NBOOPT)#N









In addition, SR NBO creates a new  NBO  direct  access  file
(DAF) each time it is called, and closes this file upon com-
pletion (See NBOPEN and NBCLOS, Section C.9).

0 SR NBO  is  provided  a  memory  vector,  CORE,  which  is
`MEMORY' double precision words in length.  For modest-sized
calculations (e.g. 10 heavy atoms with a  double-zeta  basis
set), a vector of 50,000 words should be adequate.  Although
SR NBO performs an initial partitioning of this memory  vec-
tor, the majority of the dynamic memory allocation occurs in
the NAO and NBO/NLMO formation routines, described  in  Sec-
tions C.5.3 and C.5.4.

0 An array of job options, NBOOPT(10), is also passed to  SR
NBO.   These job options identify the current version of the
NBO program (i.e., the identity of the ESS calling program),
control  program  input and execution, and determine several



                       July 11, 1995





                          - 116 -


of
the default options of the NBO analysis,  as  summarized  in
the  following  table.  [Entries marked with an asterisk (*)
contain  information  pertaining  to  the  identity  or  job
options  of the calling ESS program, and thus are of special
concern to the programmer.]

#IDESCRIPTION#N


Do nothing  (return  control  to  calling  program)  Perform
Natural  Population Analysis (NPA) only Perform NPA/NBO/NLMO
analyses, normal program run Perform NPA/NBO/NLMO  analyses,
don't  read  $NBO  keylist Initiate energetic analysis, read
one deletion from $DEL Complete  energetic  analysis,  print
the energy change

SCF density MP first order density MP2 density  MP3  density
MP4  density  CI one-particle density CI density QCI/CC den-
sity Density correct to second order

Perform the NBO/NLMO dipole analysis (force the DIPOLE  key-
word)

Allow strongly delocalized Lewis structures (force the RESO-
NANCE keyword)

Spin-annihilated UHF (AUHF) wavefunction (unused)

(unused)

General version of the NBO program  (GENNBO)  AMPAC  version
GAMESS version HONDO version GAUSSIAN-8x version



These options are read by job initialization routines  (Sec-
tion  C.5.2) and stored in COMMON/NBOPT/, where they control
events throughout the program.  [Note that NBOOPT(2) is only
used by the Gaussian versions.]


#IC.5.2 Job Initialization Routines#N

0 The  routines  of  this  section  initialize  the  default
options  and parameters, read and store the user's $NBO key-
word options:


This routine  sets  default  option  flags  (COMMON/NBOPT/),
default  logical  file  numbers  (COMMON/NBIO/), and default
thresholds (COMMON/NBTHR/) for the NBO  program.   In  addi-
tion,  SR NBOSET interprets the NBOOPT array, setting option
flags appropriately.



                       July 11, 1995





                          - 117 -


This routine is primarily responsible for reading  and  set-
ting  option flags (COMMON/NBOPT/) according to the keywords
specified in the $NBO keylist.  It reads the  $NBO  keywords
using  the  free  format  routines described in Section C.8,
continuing until the word ``$END'' terminates  the  keylist.
Options  which are incompatible with the chosen wavefunction
or program version are `shut off',  and  other  options  are
`turned  on'  in accord with the requested print level ($NBO
keyword PRINT).  All keywords which are selected in the $NBO
keylist are echoed in the output file.


Determines the scratch memory requirements of the  NBO  pro-
gram,  as  determined  by  the  options selected in the $NBO
keylist.  Program execution halts if the memory requirements
exceed the available memory.


#IC.5.3 NAO Formation Routines#N

0 The principal task of this cluster of routines is to  con-
trol  the formation of the NAOs from the input AO basis.  In
addition, these routines are responsible for the writing (to
an  external  file)  or  printing  (to the output file) of a
variety of matrices in the AO, PNAO,  and  NAO  basis  sets,
according to job options requested in the $NBO keylist.  The
first set of routines are called by SR NBO:


This is the principal controller routine for  non-orthogonal
basis sets.  The scratch vector A is partitioned within this
routine according to the memory requirements of the NAO sub-
programs.


This routine `simulates' SR NAODRV in the case  of  a  semi-
empirical calculation, where the (orthonormal) basis AOs are
the presumed effective valence shell atomic orbitals, and no
NAO transformation is needed.


Performs the transformation and analysis of  the  open-shell
AO  density  matrix  (alpha  or beta spin) to the NAO basis.
This routine employs the AO to NAO transformation, T, deter-
mined by SR NAODRV:


Simulates SR DMNAO for the open-shell  semi-empirical  case,
when no transformation is required.


Principal driver program for NBO formation; Section C.5.4.

The next set of routines are called by the main NAO  driver,



                       July 11, 1995





                          - 118 -


SR
NAODRV.  They include  the  principal  subroutine,  SR  NAO,
which generates the NAOs:


Performs the similarity transformation S#ut#d*A*S leading to
Mulliken  populations,  with  S  = overlap matrix, A = bond-
order matrix.


Evaluates Mulliken gross  populations  and  performs  Mayer-
Mulliken bond-order analysis (requires bond order matrix).


Performs the decomposition of `raw' cartesian #Id#N,  #If#N,
or  #Ig#N  AO  sets  to  pure  angular symmetry AOs (e.g., 6
cartesian #Id#N7 arr 5 pure #Id#N +  1  #Is#N);  cf.  Section
B.7.5.


This is the principal routine for formation of NAOs, follow-
ing  closely  the  algorithm  described by A. E. Reed, R. B.
Weinstock, and F. Weinhold, #IJ. Chem. Phys. #B83#N, 735-746
(1985).


This is the principal routine for  performing  and  printing
out  natural population analysis (NPA).  The routine assigns
orbital labels and energies and writes out the NPA,  natural
electron  configuration  (NEC),  NAO-Wiberg  bond  index and
overlap-weighted bond population tables.  [Thresholds  TEST,
TEST2,  ALLOW,  ALLOW2 test for numerical conservation of an
integer number of electrons.]


Forms and outputs NCOL columns of the transformation  matrix
to  MOs  from a chosen localized set, specified by INDEX = 2
(NAO), 3 (NHO), 4 (NBO), or 5 (NLMO). Input matrix T is  the
transformation from AOs to the basis set specified by INDEX,
and matrices TMO, C, and SCR are scratch arrays employed  by
this routine.

#NThe remaining routines of this section are auxiliary  sub-
routines called by SR NAO to perform individual steps of the
NAO algorithm:


Averages the AO density matrix elements over the 2+  1  com-
ponents  of  for  a  particular  atom, and loads the density
matrix and overlap integrals for the orbitals of LISTAO into
matrices A, B, respectively.


Solves  the  generalized   eigenvalue   problem   (A   minus



                       July 11, 1995





                          - 119 -


EVAL*B)*C
= 0 to diagonalize an atomic block.


Selects the `occupied' NAOs to be included  in  the  natural
minimal  basis set for a particular atom (up to Z = 105) and
angular momentum symmetry  type  (L),  and  stores  them  in
LSTOCC.


Recomputes symmetry-averaged occupancy  weights  for  PNAOs.
This   routine   is   only  used  in  conjunction  with  the
`PAOPNAO=R' keyword.


This subroutine implements the occupancy-weighted  symmetric
orthogonalization  (OWSO),  a  key  feature of the NAO algo-
rithm.  [Note that BLK and BIGBLK  share  the  same  storage
area,  though they are dimensioned differently.  The routine
includes three numerical thresholds, WTTHR  (10#uminus  3#d)
for  occupancy  weight,  DIAGTH  (10#uminus 12#d) for Jacobi
diagonalization, and DANGER (10#u3#d) for linear  dependence
difficulties.]


Schmidt orthogonalization of column vectors of T.


#NComputes new Rydberg NAOs after Schmidt  orthogonalization
of the Rydberg space to the NMB set.



#NDiagonalizes an atomic Rydberg block and updates the  PNAO
transformation matrix.


Partitions Rydbergs into `significantly occupied' (>  WTTHR)
and  `negligibly occupied' (ts, assigning the latter to have
equal (non-zero) occupancy weighting.  This avoids numerical
singularities  associated  with the OWSO occupancy weighting
for orbitals of negligible occupancy, effectively  replacing
OWSO  by  ordinary L8mlaut owdin-orthog#|onalization of these
`residual'  Rydbergs  among  themselves.   [Threshold  WTTHR
(10#uminus   4#d)  controls  singularities  of  the  inverse
square-root weighting matrix.]


Rediagonalizes the atomic density matrix blocks  after  sym-
metry averaging.


Finds the rediagonalization transformation  for  a  specific
atomic subblock of the density matrix.



                       July 11, 1995





                          - 120 -


#IC.5.4 NBO/NLMO Formation Routines#N

0  The  master  routine  of  this  cluster  is   SRhsp   hsp
NBODRV(DM,T,A),  which partitions the scratch storage vector
(A) according to the memory requirements of the  NBO  forma-
tion  and  analysis subprograms and controls the calculation
of the transformation (T) from NAOs to NBOs  using  the  NAO
density  matrix (DM).  SR NBODRV calls either SR NATHYB (for
the default NBO  search)  or  SR  CHSDRV  (for  the  $CHOOSE
directed  NBO  search)  to form the NBOs.  It also calls the
NLMO formation routine (SR NLMO) and dipole analysis routine
(SR  DIPANL).  According to job options selected in the $NBO
keylist, SR NBODRV also transforms and outputs a variety  of
matrices  in the PNHO, NHO, PNBO, NBO, PNLMO, and NLMO basis
sets.  [Note that the first NATOMS*NATOMS elements of the  A
vector  store  the  Wiberg bond index elements determined in
the NAO routines; these should not be destroyed until calcu-
lation of NBOs is complete.]

0 The following routines are called by SR NBODRV:



#NThis routine performs the basic NBO  search,  the  central
task  of  NBO  analysis,  closely  following the description
given by J. P. Foster and F. Weinhold, #IJ. Am.  Chem.  Soc.
#B102#N,  7211-7218  (1980).   The  routine  constructs  the
orthogonal matrix (T) for the NAO to NBO transformation from
the  input  NAO  density matrix (DM).  The efficiency of the
search procedure is enhanced by using  the  NAO-Wiberg  bond
index as a `GUIDE' to order the NBO search.

[Beware the IBXM bond orbital permutation  list  (!),  which
reorders  the  LABEL  array of COMMON/NBBAS/.  The occupancy
threshold, THRESH, determines whether  an  NBO  is  accepted
during  the  search  for bond orbitals (cf. SR CYCLES).  Two
numerical  thresholds  (PRJTHR,  PRJINC)  control   possible
linear  dependencies:   In the main loops over 1-c, 2-c (and
3-c) functions, each prospective NBO is checked for possible
redundancy  with  previous  NHOs  by  the PRJEXP (projection
operator expectation value) test.  The threshold PRJTHR  for
a  `new'  hybrid is initially set conservatively low (0.20),
but will be auto-incremented by PRJINC (0.05) as  needed  to
prevent   linear   dependency;   any  numerical  singularity
triggers IALARM and causes PRJTHR to be incremented and  the
entire NBO search repeated.]



#NThis routine, the ``$CHOOSE driver,''  reads  the  $CHOOSE
keylist,   setting   up   the  arrays  NTOPO  and  I3CTR  of
COMMON/NBTOPO/ which will control the directed NBO search of
SR CHOOSE.




                       July 11, 1995





                          - 121 -


#NThis routine is essentially similar to SR NATHYB, but  the
search loops are directed by the $CHOOSE specification.


Reorders (dangerous!) the NBOs according to  bond  type  and
constituent  atomic  centers.  NBOs are ordered BD (and 3C),
CR, LP, LP*, RY*, BD* (and 3C*).  Note that this step is not
required for the proper execution of any of the NBO analysis
or NLMO formation routines, but it leads  to  more  readable
output.


Examines PNHO overlaps to determine whether NBOs were  prop-
erly  labelled  as `bonds' (unstarred, Lewis) or `antibonds'
(starred, non-Lewis)  in  the  NBO  formation  routines  (SR
NATHYB  and  SR  CHOOSE).   If  incorrect nodal character is
recognized in a bond or antibond (generally indicative of an
excited  state),  a  warning  is  printed and the orbital is
relabelled.  Note that this will probably mix the NBO order-
ing set by SR SRTNBO.


Prints out  the  principal  table  (Section  A.3.3)  of  NBO
analysis  [using the IBXM ordering!], expressing each NHO in
#Isp#u #d#N form.


Analyzes input hybrid for polarization coefficient and  per-
centages  of  each angular momentum component (accepts up to
#Ig#N orbitals).


Forms the NAO to NHO transformation (THYB) and saves  it  on
the DAF.


Computes hybrid directionality and bond  bending  angles  as
determined  from  percentage  #Ip#N-character  for  selected
NBOs, and prints the BEND table (Section A.3.4).   [Keyword-
selectable  thresh#|olds  ATHR  (angular deviation), PTHR (%
#Ip#N-character), and ETHR (occupancy) control printing.]


Finds direction and percentage #Ip#N-character  of  a  given
hybrid.


Finds `molecular units' from NBO connectivity.


Classifies NBOs according to donor/acceptor type, number  of
atomic centers, and parent molecular unit.





                       July 11, 1995





                          - 122 -


Performs the 2nd-order perturbation theory  energy  analysis
of the NBO Fock matrix and prints the table (Section A.3.5).
[Thresholds ETHR1 (intramolecular) and  ETHR2  (intermolecu-
lar) control printing.]


Prepares and prints the NBO summary table (Section A.3.6).


Assembles  the  delocalization  list,  LIST(NL),   for   the
IBO#uth#d NBO.  Only intramolecular and intermolecular delo-
calizations which  are  stronger  than  THR1  and  THR2  (in
kcalhsp  mol#uminus  1#d), respectively, are included in the
list.


Builds a character string containing delocalization informa-
tion for the NBO summary table.


This is the main routine for  determination  of  the  NLMOs,
following closely the description given by A. E. Reed and F.
Weinhold,  #IJ.  Chem.  Phys.  #B83#N,   1736-1740   (1985).
[Numerical   thresholds   DIFFER   (10#uminus   5#d),   DONE
(10#uminus 10#d), and EPS (10#uminus 11#d) control the modi-
fied Jacobi diagonalizations.]


#NPrints out details of the NAO7arr NLMO  transformation  and
the NAO/NLMO bond order table (Section B.6.2).


Calculates and prints out the DIPOLE analysis table (Section
B.6.3).


Evaluates the #Ix,y,z#N (INDEX =  1,2,3)  electronic  dipole
moment  contributions,  including  delocalization  contribu-
tions, for each occupied NBO.


Evaluates the nuclear contributions  (DX,  DY,  DZ)  to  the
molecular dipole moment.

The following routines are called by SR NATHYB and SR CHOOSE
in calculating the NBOs.  Overall supervision of this set of
routines is exercised by  SR  CYCLES.   Other  routines  are
associated with specific steps of the NBO algorithm:


Performs the first step in the search for NBOs.   This  rou-
tine  identifies  core orbitals and depletes the NAO density
matrix of their contributions.




                       July 11, 1995





                          - 123 -


This function returns zero (no projection wanted)  if  still
on  the  same  atomic  center,  or  one (projection operator
should be formed) if this is a new center.


`Depletes' density matrix of contribution from bond  orbital
(BORB),  by  subtracting  its diagonal contribution from the
spectral expansion of the density  operator.   This  insures
that  the  same electron pair will not be found twice in the
NBO loops.


Loads the appropriate atomic blocks of  the  density  matrix
into  the local (2-c, 3-c) density matrix subblock (BLK), in
preparation for diagonalization.


Determines how much of a prospective bond orbital (BORB)  is
composed  of  hybrids already used.  The projection operator
onto the space of previously accepted  hybrids  is  used  to
evaluate  the  expectation value of each hybrid component of
BORB.


Decomposes bond orbital (BORB) into  constituent  normalized
hybrids and stores them in the hybrid array (Q).


Performs symmetric (L8mlaut owdin) orthogonalization on occu-
pied  atomic hybrids (PNHOs) to give final NHOs.  [Threshold
TOOSML (10#uminus 4#d) turns on the alarm (IALARM)  to  warn
of numerical instabilities due to linear dependence.]


Forms projection matrix  to  annihilate  components  of  the
occupied atomic hybrids on a given center.


This routine augments the set of occupied atomic hybrids  on
a  center  with a sufficient number of Rydberg AOs (in order
of occupancy) to complete the span of the basis set on  that
atom.


Diagonalizes each 2x2 block of the  density  matrix  in  the
basis  of final NHOs to get the optimal polarization coeffi-
cients for each NBO.


Constructs the final NAO to NBO  transformation  matrix  (T)
from  the  final  array of NHOs (Q) and polarization coeffi-
cients (POL).





                       July 11, 1995





                          - 124 -


Controls the overall  search  for  an  acceptable  resonance
structure, including the lowering of the occupancy threshold
(THRESH) for  the  RESONANCE  keyword.   Decides  whether  a
structure  is  acceptable, initiates reordered searches over
atoms for alternative resonance structures, and returns with
the  best overall structure.  Prints the initial table (Sec-
tion A.3.3) of the NBO output.


The final routines of this group are auxiliary to the forma-
tion of NLMOs, called by SR NLMO:



#NSymmetrizes the unitary transformation  matrix  (TSYM)  to
preserve  symmetries  inherent  in the density matrix, using
symmetric orthogonalization of  columns  (if  necessary)  to
preserve unitarity.


Symmetric orthogonalization of a set of column vectors  (T).
[Thresholds  DIAGTH (10#uminus 12#d) for off-diagonal Jacobi
diagonalization and DANGER (10#u3#d) to detect singularities
of  the  overlap  matrix;  all eigenvalues of S must be less
than DIAGTH*DANGER.] #BC.6 ENERGY ANALYSIS  ROUTINES  (GROUP
II)#N

The small set of routines in this group carry out the second
main  task  of  NBO  analysis,  the  NBO  Energetic Analysis
(``deletions,'' associated with inclusion of a $DEL keylist;
Section  B.5).   These  routines depend on the presence of a
Fock matrix, and are bypassed in any non-SCF calculation.

Overall control of Group II  routines  is  with  SR  NBOEAN,
which in turn calls the remaining programs of this group:


The task performed by this subroutine is  dependent  of  the
value of NBOOPT(1).  If set to 2, this routine initiates (by
calling SR NBODEL) the calculation of the next NBO  deletion
of  the  $DEL  keylist.  If set to 3, this routine completes
the NBO deletion by computing the energy for  the  deletion.
INTEGER  variable  IDONE  is set to 1 if no additional dele-
tions are found in the $DEL keylist.


Controls the calculation of the new AO density  matrix  from
the  requested deletion in the $DEL keylist.  A modified NBO
Fock matrix is created  (SR  DELETE)  and  diagonalized  (SR
JACOBI),  leading  to  a  new  AO density matrix (SR NEWDM).
This routine also prints the NBO  deletions  table  (Section
B.6.10).





                       July 11, 1995





                          - 125 -


Reads the $DEL list for the next deletion, deletes (sets  to
zero)  the  appropriate  elements  from the Fock matrix, and
prints out the deletion specification Section B.6.10).


Constructs a new density matrix corresponding to the deleted
Fock matrix.


Ranks the eigenvalues found in vector EIG (lowest eigenvalue
having  first  rank).  I = ARCRNK(N) is the entry whose rank
is N.


Performs the similarity transform  U#ut#d*F*U  on  a  packed
upper-triangular  matrix  F.   #BC.7 DIRECT ACCESS FILE ROU-
TINES (GROUP III)#N

0 The routines of Group III are  involved  in  communication
between  the  NBO programs and the FILE48 direct access file
(DAF), whose contents are described  in  Section  C.4.   Two
levels of I/O routines are employed.

0 The higher-level `fetch/save' routines are called directly
by  the NBO subroutines.  In most cases, the function of the
fetch/save routines can be recognized by its name  or  argu-
ment  list;  e.g.,  ``FETITL(TITLE)''  fetches the job title
line, ``FEFAO(F,IWFOCK)'' fetches the AO Fock matrix  (FAO),
and  so  forth.   Each routine can also be associated with a
logical record number (IDAR) of the direct access file (Sec-
tion C.4), where the I/O item is stored.  We list these rou-
tines in order of appearance, together with  the  associated
direct  access  file  record number(s) IDAR, without further
description:


0 In  turn,  the  fetch/save  routines  call  the  following
lower-level, primitive subprograms, which open, close, read,
write, and test the contents of the DAF (these  are  heavily
modified  versions  of the direct access file subroutines of
HONDO):


Opens a new or existing unformatted  DAF  depending  in  the
value of logical variable NEW.  Record lengths are currently
set at 256 (LENGTH) single precision words (1024 bytes), and
up to 100 (NBDAR) logical records can be written.  Note that
logical records and physical records  of  the  DAF  are  not
equivalent; single logical records can span several physical
records and need not be  ordered  sequentially.   The  array
IONBO  (in COMMON/NBODAF/) maps each logical record with its
associated physical records.  The first physical  record  of
the   DAF  is  reserved  for  COMMON/NBODAF/.   [Note:  Some
machines may require that you alter  the  parameters  LENGTH



                       July 11, 1995





                          - 126 -


(the
chosen record length) and ISINGL (a  record  length  scaling
factor).#N]


Writes NX double precision words  of  array  IX  to  logical
record number IDAR of the NBO DAF.


Reads NX double precision words of the logical record number
IDAR of the NBO DAF.


Rewrites common block /NBODAF/ on the first physical  record
of the DAF, and closes the file.


Inquires whether information  has  been  stored  in  logical
record  IDAR  of  the direct access file, and sets IDAR=0 if
the record is  empty.   #BC.8  FREE  FORMAT  INPUT  ROUTINES
(GROUP IV)#N

0 The routines of Group IV are  the  small  set  of  system-
independent  free-format  input  routines  that  are used in
reading the various keylists  and  datalists  of  the  input
file.   The routines of this group are the `primitives' that
read and interpret individual keywords or entries of a keyl-
ist.   They are called by higher-level I/O routines (such as
SR JOBOPT of Group I) throughout the NBO program.

The free-format input primitive routines are:


Initializes input from the LFNIN input file.


Reads the next `card' (line) of the input file,  and  stores
this  line  in  the integer array ICD in COMMON/NBCRD1/ with
all lower case characters converted to upper case.   Logical
variable  END in COMMON/NBCRD2/ is set to .TRUE. if the end-
of-file is encountered.


Searches input file LFNIN for the next string  of  non-blank
characters,  and  checks to see if they form an integer.  If
so, the numerical value of the integer is placed in INT.  If
not,  the logical variable ERROR is set to .TRUE. and INT is
set positive (indicating  an  ``END''  terminating  mark  or
end-of-file  was  encountered)  or negative (indicating that
the character string is not an integer).


Similar to SR IFLD, but for a real number REAL.   This  rou-
tine  will  accept  real  numbers  in a variety of different



                       July 11, 1995





                          - 127 -


formats.
For example, 1000 can be represented by 1000, 1000.0, 1.0E3,
D3, 1+3, etc.


Similar to SR IFLD and  RFLD,  but  for  a  Hollerith  array
KEYWD(LENG).   The logical variable ENDD is set to .TRUE. if
the ``END'' terminating mark or the end-of-file  is  encoun-
tered.   On return to the calling subroutine, LENG is set to
the length of the string in KEYWD or to zero if the  end-of-
file is encountered.


Searches for the next non-blank field  on  the  input  file,
reading  additional  lines  if  necessary.  Commas and equal
signs are treated as blanks, and any character string  which
follows an exclamation point is treated as an arbitrary com-
ment, and is ignored.  The contents of this field are stored
in   the   integer   array   LOOK   of   length   LENGTH  in
COMMON/NBCRD1/.


This logical function tests the equivalence of the first `L'
elements of the Hollerith strings IA and IB.
#BC.9 OTHER SYSTEM-INDEPENDENT I/O ROUTINES (GROUP V)#N

0 This section summarizes  the  I/O  routines  of  Group  V.
These  routines  perform  a  variety of auxiliary I/O tasks,
such as the reading or writing of matrices, or perform func-
tions closely related to I/O.

0 The first set of programs in this  group  are  responsible
for  searching  for  the  $GENNBO, $NBO, $CORE, $CHOOSE, and
$DEL identifiers of the job input file LFNIN:


Searches for the $GENNBO identifier.  In addition, this rou-
tine  reads in the keywords of the $GENNBO keylist (see Sec-
tion B.7), setting the option  flags  of  COMMON/NBOPT/  and
COMMON/NBGEN/ appropriately.


Searches for the $NBO identifier according  to  the  program
version  number,  NBOOPT(10).  The integer variable IDONE is
set to 0 if this identifier is located, or 1 otherwise.


Searches for the $CORE identifier according to  the  program
version number, IESS.  The integer variable ICOR is set to 1
if this identifier is located, or 0 otherwise.


Searches for the $CHOOSE identifier according to the program
version number, IESS.  The integer variable ICHS is set to 1



                       July 11, 1995





                          - 128 -


if
this identifier is located, or 0 otherwise.


Searches for the $DEL identifier according  to  the  program
version  number,  NBOOPT(10).  The integer variable IDONE is
set to 0 if this identifier is located, or 1 otherwise.

0 The remaining routines of this group perform miscellaneous
I/O functions:


Initializes the atomic core array (IATCR on COMMON/NBATOM/),
and reads the entries of the $CORE keylist.


Writes the transformation from `pure' AOs to PNAOs, the  NAO
labels  (NAOCTR,  NAOL,  and LSTOCC from COMMON/NBBAS/), and
PNAO occupancies (diagonal PNAO density matrix elements)  to
an  external  file  (LFN = minus IFLG).  Pure AOs (PAOs) are
obtained from `raw' cartesian AOs by the transformations  of
SR DFGORB.


Reads the transformation from `pure' AOs  (PAOs)  to  PNAOs,
NAO  labels, and PNAO occupancies from an external file (LFN
= minus IFLG/1000)  (cf.  SR WRPPNA).


Writes the AO to NAO transformation (fetched from the  DAF),
NAO  labels,  and the PNAO overlap matrix (also fetched from
the DAF) to an external file (LFN = minus IFLG).  Note  that
T is the PNAO overlap matrix when control is returned to the
calling routine.


Reads the AO to NAO transformation,  NAO  labels,  and  PNAO
overlap   matrix   from   an  external  file  (LFN  =  minus
IFLG/1000).  The transformation  and  overlap  matrices  are
saved  on  the  DAF,  and  the  input  AO  density matrix is
transformed to the NAO basis.  Note that T is the PNAO over-
lap matrix on return to the calling routine (cf. SR WRTNAO).


Writes the NAO to NBO transformation and  NBO  info  (LABELS
and IBXM arrays of COMMON/NBBAS/) to an external file (LFN =
minus IFLG).


Reads the NAO to NBO transformation and  NBO  info  from  an
external  disk  file (LFN = minus IFLG/1000).  The input NAO
density matrix is also transformed to the NBO basis, and the
NBO occupancies are stored in BNDOCC (cf. WRTNAB).




                       July 11, 1995





                          - 129 -


Writes the AO to NBO transformation,  the  NBO  occupancies,
and  additional  NBO  info (NBOUNI, NBOTYP, LABEL, IBXM, and
IATNO arrays) to an external disk file (LFN = minus IFLG).


Similar to SR WRTNBO but for  NLMOs.   Note  that  the  NLMO
labels are identical to the NBO labels.


Writes the atomic coordinates and AO basis  set  information
to the `AOINFO' file LFN.  The information contained in this
file is identical to that of the $COORD, $BASIS,  and  $CON-
TRACT  datalists of the GENNBO input file (see Section B.7).
For more information on the file format, see the  subroutine
source code.


Writes the `ARCHIVE' file LFN (see Section B.7).


General utility to write matrix A(MR,1) to an external  file
(LFN  =  minus  IFLG) or print it to the output file (IFLG =
number of columns to print, `FULL', `VAL', or `LEW').  TITLE
is  a  CHARACTER*80  matrix  label,  and  the  rows of A are
labelled according to the value of  INDEX  =  0  (atoms),  1
(AOs),  2  (NAOs),  3  (NHOs), 4 (NBOs), or 5 (NLMOs).  This
routine calls SR APRINT or SR AWRITE.


Prints MCOL columns of matrix A to  the  output  file.   The
format of the matrix is chosen according to the magnitude of
the largest matrix element in A (cf. SR AOUT).


Writes matrix A to external disk file LFN (cf. SR AOUT).


Reads NC columns of the matrix  A(MR,1)  from  the  external
file LFN.  The job title in the external file is returned to
the calling subroutine in the Hollerith array, JOB(20),  and
the  LOGICAL  variable  ERROR  is  set to .TRUE. if an error
occurred while reading.


Prints the matrix A(MR,MC)  to  the  standard  output  file.
This  routine  is  called  only when the print formats of SR
APRINT are unsuitable for matrix A.


Interprets the  Hollerith  array  STRING(LEN),  storing  the
result  in  IFLG.   The contents of STRING can be any of the
read/write/print parameters such as  `W38',  `PVAL',  `R43',
etc., described in Section B.2.4, and the resulting value of
IFLG  is  determined  according   to   the   discussion   of



                       July 11, 1995





                          - 130 -


COMMON/NBOPT/
in Section C.3.  When this routine is called, IFLG should be
set to its default value, LFN should be the default file for
writing or reading, and LOGICAL variable READ should be  set
to  .TRUE.  if reading from an external file is allowed. The
LOGICAL variable ERROR is set to .TRUE. if STRING  is  unin-
terpretable.


Interprets IFLG as to whether the I/O item should be printed
(IOINQR  =  `PRNT'),  read (IOINQR = `READ'), or written out
(IOINQR = `WRIT') to an external file.


Forms labels for AOs and stores them in COMMON/NBLBL/.


Forms labels for NAOs and stores them in COMMON/NBLBL/.


Forms labels for NBOs and stores them in COMMON/NBLBL/.


Forms labels for NHOs and stores them in COMMON/NBLBL/.

#BC.10 GENERAL UTILITY ROUTINES (GROUP VI)#N

#NThe utility routines of Group  VI  perform  a  variety  of
mathematical  and  other general tasks (such as solving sets
of  linear  equations),  and  are   called   from   routines
throughout  the NBO program.  They are grouped in alphabeti-
cal order (except for the final group of routines controlled
by the SR LINEQ driver):


Converts  cartesian  coordinates  (X,Y,Z)  to  corresponding
polar  angle  THETA  and  azi#|muthal angle PHI in spherical
polar coordinates.


LOGICAL function BDFIND is set to  .TRUE.  if  there  is  at
least one bond between atoms IAT, JAT.


Builds a `chemical formula' for the list of atoms  in  LISTA
having been identified as belonging to a particular `molecu-
lar unit'.  The chemical formula is stored in the  Hollerith
array ISTR(NL).


Consolidates an upper-triangular (AUT) and  lower-triangular
(ALT) matrix in a single matrix, stored in AUT.





                       July 11, 1995





                          - 131 -


_2.

_C_o_n_v_e_r_t_s _t_h_e _H_o_l_l_e_r_i_t_h _a_r_r_a_y _I_J(_L_E_N)  _i_n_t_o  _a_n  _i_n_t_e_g_e_r  _I_K.
_T_h_i_s _i_s _t_h_e _i_n_v_e_r_s_e _o_f _S_R _I_D_I_G_I_T.


_C_o_n_v_e_r_t_s _a _2-_d_i_g_i_t _i_n_t_e_g_e_r _N  _t_o  _t_w_o  _H_o_l_l_e_r_i_t_h  _c_h_a_r_a_c_t_e_r_s
_N_C_1, _N_C_2.


_C_o_p_i_e_s _m_a_t_r_i_x _A _t_o _m_a_t_r_i_x _B.


_S_t_o_r_e_s _t_h_e _n_o_m_i_n_a_l ``_c_o_r_e _t_a_b_l_e,'' _g_i_v_i_n_g _t_h_e _n_u_m_b_e_r _o_f _c_o_r_e
#_I_s#_N, #_I_p#_N, #_I_d#_N, #_I_f#_N _o_r_b_i_t_a_l_s _f_o_r _e_l_e_m_e_n_t_s _1-_1_0_5 (_H _t_o
_L_w, _a_n_d _e_l_e_m_e_n_t_s _1_0_4, _1_0_5).  _T_h_i_s _t_a_b_l_e _c_o_n_t_r_o_l_s _t_h_e  _n_u_m_b_e_r
_o_f  _h_i_g_h-_o_c_c_u_p_a_n_c_y  _u_n_h_y_b_r_i_d_i_z_e_d  _N_A_O_s _t_h_a_t _w_i_l_l _b_e _i_s_o_l_a_t_e_d
_a_n_d _r_e_m_o_v_e_d _a_s _c_o_r_e _N_B_O_s (_t_a_k_i_n_g _a_c_c_o_u_n_t _a_l_s_o _o_f _a_n_y  _e_f_f_e_c_-
_t_i_v_e _c_o_r_e _p_o_t_e_n_t_i_a_l).


_D_e_c_o_m_p_o_s_e_s _a _H_o_l_l_e_r_i_t_h _v_a_r_i_a_b_l_e _I _i_n_t_o _i_t_s  _f_o_u_r  _i_n_d_i_v_i_d_u_a_l
_H_o_l_l_e_r_i_t_h `_b_y_t_e_s' _I_B_Y_T_E(_4).


_H_a_l_t_s _t_h_e _e_x_e_c_u_t_i_o_n _o_f _t_h_e _N_B_O _p_r_o_g_r_a_m _i_f _a_n  _u_n_r_e_c_o_g_n_i_z_a_b_l_e
_k_e_y_w_o_r_d _i_s _f_o_u_n_d _i_n _t_h_e $_N_B_O _k_e_y_l_i_s_t.


_C_o_n_v_e_r_t_s _t_h_e _I_N_T_E_G_E_R _v_a_r_i_a_b_l_e _K_I_N_T _i_n _t_h_e _f_i_r_s_t _N_D  _e_l_e_m_e_n_t_s
_o_f  _t_h_e _H_o_l_l_e_r_i_t_h _a_r_r_a_y _I_K(_M_A_X_D).  _T_h_i_s _i_s _t_h_e _i_n_v_e_r_s_e _o_f _S_R
_C_O_N_V_I_N.


_T_h_i_s _H_o_l_l_e_r_i_t_h _f_u_n_c_t_i_o_n _d_e_t_e_r_m_i_n_e_s _w_h_e_t_h_e_r  _t_h_e  _I_B_O7_a_r_r  _J_B_O
_d_e_l_o_c_a_l_i_z_a_t_i_o_n  _i_s  _v_i_c_i_n_a_l  (`_v'), _g_e_m_i_n_a_l (`_g'), _o_r _r_e_m_o_t_e
(`_r'), _b_a_s_e_d _o_n _t_h_e _d_e_r_i_v_e_d _N_B_O _c_o_n_n_e_c_t_i_v_i_t_y.



_3.  _D_i_a_g_o_n_a_l_i_z_e_s _a _r_e_a_l _s_y_m_m_e_t_r_i_c _m_a_t_r_i_x _b_y _t_h_e _J_a_c_o_b_i _r_o_t_a_-
_t_i_o_n_s  _m_e_t_h_o_d.   _I_f _I_C_O_N_T_R=_0, _a _s_t_a_n_d_a_r_d _J_a_c_o_b_i _d_i_a_g_o_n_a_l_i_z_a_-
_t_i_o_n (_u_n_c_o_n_s_t_r_a_i_n_e_d  _2_x_2  _r_o_t_a_t_i_o_n_s)  _i_s  _c_a_r_r_i_e_d  _o_u_t.   _I_f
_I_C_O_N_T_R=_1,  _t_h_e  _a_l_g_o_r_i_t_h_m  _i_s _p_r_e_v_e_n_t_e_d _f_r_o_m _m_i_x_i_n_g _o_r_b_i_t_a_l_s
_t_h_a_t _a_r_e _d_e_g_e_n_e_r_a_t_e _w_i_t_h_i_n `_D_I_F_F_E_R' _i_f _t_h_e _o_f_f-_d_i_a_g_o_n_a_l _e_l_e_-
_m_e_n_t  _c_o_n_n_e_c_t_i_n_g  _t_h_e_m  _i_s  _l_e_s_s  _t_h_a_n `_D_I_F_F_E_R'.  [_T_h_r_e_s_h_o_l_d
_D_I_F_F_E_R (_1_0#_u_m_i_n_u_s  _5#_d)  _c_o_n_t_r_o_l_s  _d_e_g_e_n_e_r_a_t_e  _m_i_x_i_n_g,  _D_O_N_E
(_1_0#_u_m_i_n_u_s  _1_3#_d)  _i_s  _t_h_e _m_a_x_i_m_u_m _a_l_l_o_w_e_d _o_f_f-_d_i_a_g_o_n_a_l _e_l_e_-
_m_e_n_t, _a_n_d _E_P_S (_0._5_x_1_0#_u_m_i_n_u_s _1_3#_d) _i_s _a _n_u_m_b_e_r _b_e_t_w_e_e_n  _D_O_N_E
_a_n_d _t_h_e _m_a_c_h_i_n_e _p_r_e#|_c_i_s_i_o_n.]


_T_h_i_s _r_o_u_t_i_n_e _c_a_r_r_i_e_s _o_u_t _a  `_l_i_m_i_t_e_d'  _t_r_a_n_s_f_o_r_m_a_t_i_o_n  _o_f  _a
_m_a_t_r_i_x  (_T),  _u_s_i_n_g  _o_n_l_y  _t_h_e _r_o_w_s _a_n_d _c_o_l_u_m_n_s _s_p_e_c_i_f_i_e_d _b_y



                       July 11, 1995





                          - 132 -


_v_e_c_t_o_r
_M.   _T_h_e  _o_p_e_r_a_t_i_o_n_s  _p_e_r_f_o_r_m_e_d  _a_r_e  _T*_A,  _A#_u_t#_d*_T*_A,   _o_r
_A#_u_t#_d*_T _a_c_c_o_r_d_i_n_g _t_o _t_h_e _v_a_l_u_e _o_f _I_O_P_T.


_M_u_l_t_i_p_l_i_e_s _s_q_u_a_r_e _m_a_t_r_i_c_e_s _A*_B (_u_s_i_n_g _s_c_r_a_t_c_h _v_e_c_t_o_r _V)  _a_n_d
_s_t_o_r_e_s _r_e_s_u_l_t _i_n _A.


_M_u_l_t_i_p_l_i_e_s _A#_u_t#_d*_B (_u_s_i_n_g _s_c_r_a_t_c_h _v_e_c_t_o_r _V) _a_n_d _s_t_o_r_e_s  _t_h_e
_r_e_s_u_l_t _i_n _B.  _T_h_e _a_l_g_o_r_i_t_h_m _a_s_s_u_m_e_s _t_h_a_t _A*_B _i_s _a _s_y_m_m_e_t_r_i_c,
_s_o _a_b_o_u_t _h_a_l_f _t_h_e _w_o_r_k _i_s _s_a_v_e_d.  [_S_R  _M_A_T_M_L_2  _i_s  _t_y_p_i_c_a_l_l_y
_t_h_e _s_e_c_o_n_d _s_t_e_p _i_n _a _s_i_m_i_l_a_r_i_t_y _t_r_a_n_s_f_o_r_m _o_f _B _b_y _A, _w_h_e_r_e _B
(_a_n_d _t_h_u_s _A#_u_t#_d*_B*_A) _i_s _s_y_m_m_e_t_r_i_c.]


_R_e_t_u_r_n_s _t_h_e (_H_o_l_l_e_r_i_t_h) _a_t_o_m_i_c _s_y_m_b_o_l _f_o_r _a_t_o_m_i_c _n_u_m_b_e_r _I_Z


_N_o_r_m_a_l_i_z_e_s _t_h_e _c_o_l_u_m_n_s _o_f _A _u_s_i_n_g _t_h_e _o_v_e_r_l_a_p _m_a_t_r_i_x _S.



_4.  _R_a_n_k_s _t_h_e _p_o_s_i_t_i_v_e _e_l_e_m_e_n_t_s _o_f _i_n_t_e_g_e_r  _L_I_S_T(_N),  _l_o_w_e_s_t
_v_a_l_u_e_s  _f_i_r_s_t.  [_R_A_N_K _a_n_d _A_R_C_R_N_K _a_r_e _i_n_t_e_g_e_r _v_e_c_t_o_r_s, _w_i_t_h _I
= _A_R_C_R_N_K(_N) _i_f _L_I_S_T(_I) _i_s _t_h_e _e_l_e_m_e_n_t _o_f _r_a_n_k _N.]


_P_a_c_k_s _t_h_e _u_p_p_e_r-_t_r_i_a_n_g_u_l_a_r _p_o_r_t_i_o_n _o_f _t_h_e  _s_y_m_m_e_t_r_i_c  _m_a_t_r_i_x
_T(_N_B_A_S,_N_B_A_S) _t_h_e _f_i_r_s_t _L_2 _e_l_e_m_e_n_t_s _o_f _T.


_O_r_d_e_r_s _t_h_e _e_n_t_r_i_e_s _o_f  _v_e_c_t_o_r  _E_I_G,  _h_i_g_h_e_s_t  _v_a_l_u_e_s  _f_i_r_s_t.
_A_R_C_R_N_K(_I)  _i_s  _t_h_e _o_l_d _l_o_c_a_t_i_o_n _o_f _t_h_e _I#_u_t_h#_d _h_i_g_h_e_s_t _v_a_l_u_e
_i_n _E_I_G.  _O_n _r_e_t_u_r_n, _E_I_G(_I) _i_s  _t_h_e  _I#_u_t_h#_d  _h_i_g_h_e_s_t  _v_a_l_u_e.
[_E_n_t_r_i_e_s  _a_r_e _n_o_t _s_w_i_t_c_h_e_d _u_n_l_e_s_s _t_h_e_y _d_i_f_f_e_r _b_y _m_o_r_e _t_h_a_n _a
_D_I_F_F_E_R (_5_x_1_0#_u_m_i_n_u_s _8#_d) _t_h_r_e_s_h_o_l_d.]


_P_e_r_f_o_r_m_s _t_h_e _g_e_n_e_r_a_l _s_i_m_i_l_a_r_i_t_y _t_r_a_n_s_f_o_r_m _T#_u_t#_d*_A*_T _o_f _A _b_y
_T, _u_s_i_n_g _s_c_r_a_t_c_h _v_e_c_t_o_r _V.


_P_e_r_f_o_r_m_s _t_h_e `_f_a_s_t' _s_i_m_i_l_a_r_i_t_y _t_r_a_n_s_f_o_r_m _S#_u_t#_d*_A*_S,  _a_s_s_u_m_-
_i_n_g _t_h_e _r_e_s_u_l_t _i_s _s_y_m_m_e_t_r_i_c.


_T_r_a_n_s_p_o_s_e_s _t_h_e _m_a_t_r_i_x _A: _A7_a_r_r _A#_u_t#_d.


_U_n_p_a_c_k_s _a_n _u_p_p_e_r _t_r_i_a_n_g_u_l_a_r _m_a_t_r_i_x  (_v_e_c_t_o_r  _o_f  _l_e_n_g_t_h  _L_2)
_i_n_t_o _a _s_y_m_m_e_t_r_i_c _m_a_t_r_i_x _T(_N_B_A_S,_N_B_A_S).





                       July 11, 1995





                          - 133 -


_S_p_e_c_i_f_i_e_s _t_h_e _n_o_m_i_n_a_l ``_v_a_l_e_n_c_e _t_a_b_l_e,'' _g_i_v_i_n_g  _t_h_e  _n_u_m_b_e_r
_o_f _v_a_l_e_n_c_e _A_O_s _o_f _e_a_c_h _s_y_m_m_e_t_r_y _t_y_p_e _f_o_r _e_l_e_m_e_n_t_s _1-_1_0_5.


_E_v_a_l_u_a_t_e_s _E_u_c_l_i_d_e_a_n _l_e_n_g_t_h _o_f _v_e_c_t_o_r _X.


_T_h_i_s _a_n_d _t_h_e _t_h_r_e_e _f_o_l_l_o_w_i_n_g _r_o_u_t_i_n_e_s _c_o_n_s_t_i_t_u_t_e _t_h_e  _l_i_n_e_a_r
_e_q_u_a_t_i_o_n_s  _p_a_c_k_a_g_e _f_o_r _s_o_l_v_i_n_g _t_h_e _s_y_s_t_e_m _A*_X = _B _f_o_r _m_a_t_r_i_x
_X _b_y _t_h_e _m_e_t_h_o_d _o_f _G_a_u_s_s_i_a_n _e_l_i_m_i_n_a_t_i_o_n.


_S_u_p_p_o_r_t_s _S_R _L_I_N_E_Q.


_S_u_p_p_o_r_t_s _S_R _L_I_N_E_Q.


_S_u_p_p_o_r_t_s _S_R _L_I_N_E_Q.  #_B_C._1_1 _S_Y_S_T_E_M-_D_E_P_E_N_D_E_N_T _D_R_I_V_E_R  _R_O_U_T_I_N_E_S
(_G_R_O_U_P _V_I_I)#_N

_0 _T_h_e _r_o_u_t_i_n_e_s  _o_f  _G_r_o_u_p  _V_I_I  _c_o_m_p_r_i_s_e  _t_h_e  _s_e_t  _o_f  _E_S_S-
_d_e_p_e_n_d_e_n_t  _d_r_i_v_e_r  _r_o_u_t_i_n_e_s  _w_h_i_c_h  _i_n_i_t_i_a_t_e _t_h_e _N_B_O _a_n_d _N_B_O
_e_n_e_r_g_e_t_i_c _a_n_a_l_y_s_e_s  _a_n_d  _p_r_o_v_i_d_e  _t_h_e  _N_B_O  _p_r_o_g_r_a_m  _w_i_t_h  _a
_v_a_r_i_e_t_y  _o_f  _i_n_f_o_r_m_a_t_i_o_n  _a_b_o_u_t _t_h_e _e_l_e_c_t_r_o_n_i_c _w_a_v_e_f_u_n_c_t_i_o_n.
_T_h_i_s _s_e_c_t_i_o_n _p_r_o_v_i_d_e_s _a _b_r_i_e_f, _g_e_n_e_r_i_c _d_e_s_c_r_i_p_t_i_o_n  _o_f  _e_a_c_h
_o_f  _t_h_e  _d_r_i_v_e_r  _r_o_u_t_i_n_e_s.   _I_f _y_o_u _i_n_t_e_n_d _t_o _w_r_i_t_e _a _s_e_t _o_f
_r_o_u_t_i_n_e_s _f_o_r _a_n _E_S_S _p_r_o_g_r_a_m _n_o_t _s_u_p_p_o_r_t_e_d _b_y _t_h_i_s  _d_i_s_t_r_i_b_u_-
_t_i_o_n,  _r_e_f_e_r  _t_o  _t_h_e _d_r_i_v_e_r _s_o_u_r_c_e _c_o_d_e _f_o_r _a_d_d_i_t_i_o_n_a_l _g_u_i_-
_d_a_n_c_e.  _A_l_s_o, _s_e_e _S_e_c_t_i_o_n _C._1_3 _f_o_r _h_e_l_p_f_u_l _h_i_n_t_s _f_o_r _a_t_t_a_c_h_-
_i_n_g _t_h_e _N_B_O _p_r_o_g_r_a_m _t_o _a_n _E_S_S _p_a_c_k_a_g_e.

_0 _T_h_e _d_r_i_v_e_r _r_o_u_t_i_n_e_s _a_r_e _g_r_o_u_p_e_d _t_o_g_e_t_h_e_r _a_t _t_h_e _e_n_d _o_f _t_h_e
_N_B_O _s_o_u_r_c_e _c_o_d_e.  _S_i_n_c_e _m_u_l_t_i_p_l_e _v_e_r_s_i_o_n_s _o_f _e_a_c_h _d_r_i_v_e_r _a_r_e
_p_r_o_v_i_d_e_d (_o_n_e _f_o_r _e_a_c_h _s_u_p_p_o_r_t_e_d _E_S_S  _p_a_c_k_a_g_e  _a_n_d  _G_E_N_N_B_O),
_a_l_l _o_f _t_h_e _e_x_e_c_u_t_a_b_l_e _l_i_n_e_s _i_n _t_h_e_s_e _r_o_u_t_i_n_e_s _a_r_e `_c_o_m_m_e_n_t_e_d
_o_u_t' _w_i_t_h _a_n _a_s_t_e_r_i_s_k _i_n _t_h_e  _f_i_r_s_t  _c_o_l_u_m_n.   _I_n  _a_d_d_i_t_i_o_n,
_e_v_e_r_y  _l_i_n_e _o_f _t_h_e _d_r_i_v_e_r_s _h_a_s _a_n _i_d_e_n_t_i_f_i_e_r `#_I_X_X_X#_N_D_R_V' _i_n
_c_o_l_u_m_n_s _7_3-_7_8, _w_h_e_r_e `#_I_X_X_X#_N' _i_s _a _3-_l_e_t_t_e_r _i_d_e_n_t_i_f_i_e_r  _f_o_r
_t_h_e _a_s_s_o_c_i_a_t_e_d _E_S_S _p_a_c_k_a_g_e.  _I_t _i_s _t_h_e _r_e_s_p_o_n_s_i_b_i_l_i_t_y _o_f _t_h_e
_p_r_o_g_r_a_m _E_N_A_B_L_E _t_o `_u_n_c_o_m_m_e_n_t' _t_h_e _a_p_p_r_o_p_r_i_a_t_e _l_i_n_e_s  _o_f  _t_h_e
_c_o_d_e _f_o_r _t_h_e _r_e_q_u_e_s_t_e_d _p_r_o_g_r_a_m _v_e_r_s_i_o_n (_s_e_e _S_e_c_t_i_o_n _A._2).

_0 _T_h_e _s_y_s_t_e_m-_d_e_p_e_n_d_e_n_t _d_r_i_v_e_r _r_o_u_t_i_n_e_s _a_r_e:


_D_e_t_e_r_m_i_n_e_s _t_h_e _l_o_g_i_c_a_l _f_i_l_e _n_u_m_b_e_r_s _f_o_r _t_h_e _i_n_p_u_t _a_n_d _o_u_t_p_u_t
_f_i_l_e_s  (_L_F_N_I_N  _a_n_d _L_F_N_P_R) _o_f _t_h_e _p_a_r_e_n_t _p_r_o_g_r_a_m, _i_n_i_t_i_a_l_i_z_e_s
_t_h_e _N_B_O_O_P_T _j_o_b _o_p_t_i_o_n _a_r_r_a_y _S_e_c_t_i_o_n  _C._5._1),  _a_n_d  _i_n_i_t_i_a_t_e_s
_t_h_e  _N_B_O  _a_n_a_l_y_s_i_s  (_S_R  _N_B_O)  _a_n_d  _e_n_e_r_g_e_t_i_c  _a_n_a_l_y_s_i_s  (_S_R
_N_B_O_E_A_N).  _T_h_i_s _r_o_u_t_i_n_e _i_s _t_h_e _o_n_l_y _r_o_u_t_i_n_e _o_f _t_h_e  _N_B_O  _p_r_o_-
_g_r_a_m _c_a_l_l_e_d _d_i_r_e_c_t_l_y _b_y _t_h_e _p_a_r_e_n_t _E_S_S _p_a_c_k_a_g_e.





                       July 11, 1995





                          - 134 -


_I_n_t_e_r_r_o_g_a_t_e_s _t_h_e _s_c_r_a_t_c_h _f_i_l_e_s  _a_n_d  _C_O_M_M_O_N  _b_l_o_c_k_s  _o_f  _t_h_e
_p_a_r_e_n_t  _p_r_o_g_r_a_m,  _p_r_o_v_i_d_i_n_g  _t_h_e  _N_B_O  _p_r_o_g_r_a_m _w_i_t_h _r_e_q_u_i_r_e_d
_i_n_f_o_r_m_a_t_i_o_n _o_f _t_h_e _e_l_e_c_t_r_o_n_i_c _w_a_v_e_f_u_n_c_t_i_o_n _v_i_a _t_h_e _N_B_O  _C_O_M_-
_M_O_N  _b_l_o_c_k_s  _a_n_d  _F_I_L_E_4_8 _d_i_r_e_c_t _a_c_c_e_s_s _f_i_l_e.  (_N_o_t_e _t_h_a_t _f_o_r
_G_E_N_N_B_O, _t_h_i_s _r_o_u_t_i_n_e _d_i_r_e_c_t_s _t_h_e _i_n_p_u_t _o_f  _i_n_f_o_r_m_a_t_i_o_n  _f_r_o_m
_t_h_e  _G_E_N_N_B_O  _i_n_p_u_t _f_i_l_e, _F_I_L_E_4_7.)  _T_h_e _N_B_O _C_O_M_M_O_N _b_l_o_c_k_s _a_n_d
_F_I_L_E_4_8 _r_e_c_o_r_d_s _w_h_i_c_h _m_u_s_t _b_e _i_n_i_t_i_a_l_i_z_e_d _b_y  _S_R  _F_E_A_O_I_N  _a_r_e
_d_i_s_c_u_s_s_e_d  _i_n  _S_e_c_t_i_o_n_s _C._3, _C._4.  _A_d_d_i_t_i_o_n_a_l _i_n_f_o_r_m_a_t_i_o_n _o_n
_t_h_e _C_O_M_M_O_N _b_l_o_c_k_s _a_n_d _s_c_r_a_t_c_h _f_i_l_e_s _o_f _t_h_e _p_a_r_e_n_t _E_S_S  _p_a_c_k_-
_a_g_e _i_s _p_r_o_v_i_d_e_d _i_n _t_h_e _A_p_p_e_n_d_i_c_e_s.



_P_e_r_f_o_r_m_s _o_n_e  _o_f  _t_w_o  _t_a_s_k_s,  _d_e_p_e_n_d_i_n_g  _o_f  _t_h_e  _v_a_l_u_e  _o_f
_N_B_O_O_P_T(_1).  _I_f _N_B_O_O_P_T(_1) _i_s _s_e_t _t_o _2, _S_R _D_E_L_S_C_F _p_r_o_v_i_d_e_s _t_h_e
_p_a_r_e_n_t _E_S_S _p_r_o_g_r_a_m _w_i_t_h _t_h_e  _m_o_d_i_f_i_e_d  _d_e_n_s_i_t_y  _m_a_t_r_i_x  _g_e_n_-
_e_r_a_t_e_d  _b_y  _t_h_e _N_B_O _e_n_e_r_g_e_t_i_c _a_n_a_l_y_s_i_s _r_o_u_t_i_n_e_s.  _T_h_e _p_a_r_e_n_t
_p_r_o_g_r_a_m _w_i_l_l _t_h_e_n _c_o_m_p_u_t_e _t_h_e ``_d_e_l_e_t_i_o_n _e_n_e_r_g_y''  _f_o_r  _t_h_i_s
_m_o_d_i_f_i_e_d  _w_a_v_e_f_u_n_c_t_i_o_n.  _I_f _N_B_O_O_P_T(_1) _i_s _s_e_t _t_o _3, _S_R _D_E_L_S_C_F
_f_e_t_c_h_e_s _t_h_e _d_e_l_e_t_i_o_n _e_n_e_r_g_y  _f_r_o_m  _t_h_e  _p_a_r_e_n_t  _p_r_o_g_r_a_m  _a_n_d
_w_r_i_t_e_s  _i_t  _t_o  _t_h_e  _F_I_L_E_4_8 _d_i_r_e_c_t _a_c_c_e_s_s _f_i_l_e.  (_T_h_e _N_B_O_O_P_T
_a_r_r_a_y _i_s _d_i_s_c_u_s_s_e_d _i_n _S_e_c_t_i_o_n _C._5._1).

#_B_C._1_2 _G_E_N_N_B_O _A_U_X_I_L_I_A_R_Y _R_O_U_T_I_N_E_S#_N

_0 _A_n _a_d_d_i_t_i_o_n_a_l _s_e_t _o_f _r_o_u_t_i_n_e_s _i_s _p_r_o_v_i_d_e_d _f_o_r  _t_h_e  _G_E_N_N_B_O
_s_t_a_n_d-_a_l_o_n_e  _p_r_o_g_r_a_m.   _T_h_e_s_e  _r_o_u_t_i_n_e_s  _a_r_e  _c_a_l_l_e_d  _b_y _t_h_e
_G_E_N_N_B_O _d_r_i_v_e_r _r_o_u_t_i_n_e _F_E_A_O_I_N _a_n_d _a_r_e _r_e_s_p_o_n_s_i_b_l_e _f_o_r _r_e_a_d_i_n_g
_t_h_e  _d_a_t_a_l_i_s_t_s _o_f _t_h_e _G_E_N_N_B_O _i_n_p_u_t _f_i_l_e.  _E_a_c_h _o_f _t_h_e_s_e _r_o_u_-
_t_i_n_e_s _r_e_w_i_n_d_s _t_h_e _i_n_p_u_t _f_i_l_e _b_e_f_o_r_e  _s_e_a_r_c_h_i_n_g  _s_e_q_u_e_n_t_i_a_l_l_y
_f_o_r  _i_t_s  _a_s_s_o_c_i_a_t_e_d _d_a_t_a_l_i_s_t.  _T_h_u_s, _t_h_e _o_r_d_e_r _o_f _d_a_t_a_l_i_s_t_s
(_a_s _w_e_l_l _a_s _k_e_y_l_i_s_t_s) _i_n _t_h_e _i_n_p_u_t _f_i_l_e _i_s _i_m_m_a_t_e_r_i_a_l.  _E_a_c_h
_r_o_u_t_i_n_e  _a_l_s_o  _c_h_e_c_k_s  _t_h_a_t  _a_l_l _r_e_q_u_i_r_e_d _i_n_f_o_r_m_a_t_i_o_n _i_n _t_h_e
_d_a_t_a_l_i_s_t _i_s _g_i_v_e_n _a_n_d _s_t_o_r_e_s _t_h_i_s _i_n_f_o_r_m_a_t_i_o_n _o_n _t_h_e  _F_I_L_E_4_8
_d_i_r_e_c_t _a_c_c_e_s_s _f_i_l_e _o_r _i_n _t_h_e _N_B_O _C_O_M_M_O_N _b_l_o_c_k_s.

_0 _B_e_l_o_w _w_e _l_i_s_t _e_a_c_h _G_E_N_N_B_O  _a_u_x_i_l_i_a_r_y  _r_o_u_t_i_n_e,  _i_n_d_i_c_a_t_i_n_g
_i_t_s _a_s_s_o_c_i_a_t_e_d _d_a_t_a_l_i_s_t, _b_u_t _w_i_t_h_o_u_t _f_u_r_t_h_u_r _e_x_p_l_a_n_a_t_i_o_n:


#_B_C._1_3 _A_T_T_A_C_H_I_N_G _N_B_O _T_O _A _N_E_W _E_S_S _P_R_O_G_R_A_M#_N

_T_h_i_s _s_e_c_t_i_o_n _b_r_i_e_f_l_y _o_u_t_l_i_n_e_s _t_h_e  _s_t_e_p_s  _t_o  _b_e  _c_o_n_s_i_d_e_r_e_d
_w_h_e_n  _a_t_t_a_c_h_i_n_g _t_h_e _N_B_O _p_r_o_g_r_a_m _t_o _a _n_e_w _E_S_S _p_a_c_k_a_g_e _t_h_a_t _i_s
_n_o_t _s_u_p_p_o_r_t_e_d _b_y _t_h_i_s _d_i_s_t_r_i_b_u_t_i_o_n.

_I_n _g_e_n_e_r_a_l, _y_o_u _s_h_o_u_l_d _t_r_y _t_o  _i_d_e_n_t_i_f_y  _t_h_e  _s_u_p_p_o_r_t_e_d  _E_S_S
_p_a_c_k_a_g_e  _t_h_a_t _i_s _m_o_s_t _s_i_m_i_l_a_r _t_o _t_h_e _E_S_S _p_a_c_k_a_g_e _y_o_u _w_i_s_h _t_o
_u_s_e, _a_n_d _t_r_y _t_o _c_r_e_a_t_e _d_r_i_v_e_r _r_o_u_t_i_n_e_s _m_o_d_e_l_l_e_d  _a_s  _c_l_o_s_e_l_y
_a_s  _p_o_s_s_i_b_l_e  _o_n _t_h_o_s_e _p_r_o_v_i_d_e_d _f_o_r _t_h_e _E_S_S.  [_I_n _f_a_c_t, _e_x_a_-
_m_i_n_i_n_g _t_h_e _s_o_u_r_c_e _c_o_d_e _f_o_r _d_r_i_v_e_r _r_o_u_t_i_n_e_s _o_f  #_I_a_l_l#_N  _s_u_p_-
_p_o_r_t_e_d _E_S_S _p_a_c_k_a_g_e_s _i_s _g_o_o_d _p_r_e_p_a_r_a_t_i_o_n _f_o_r _w_r_i_t_i_n_g _y_o_u_r _o_w_n
_d_r_i_v_e_r_s.]




                       July 11, 1995





                          - 135 -


_D_e_c_i_d_e _w_h_e_r_e _i_n _t_h_e _p_a_r_e_n_t _E_S_S _p_a_c_k_a_g_e _y_o_u _w_i_s_h  _t_o  _p_e_r_f_o_r_m
_t_h_e _N_B_O _a_n_a_l_y_s_i_s.  _T_h_i_s _w_i_l_l _n_e_c_e_s_s_a_r_i_l_y _b_e _p_l_a_c_e_d _a_f_t_e_r _t_h_e
_c_a_l_c_u_l_a_t_i_o_n _o_f _t_h_e _w_a_v_e_f_u_n_c_t_i_o_n (_a_n_d _t_h_e _a_s_s_o_c_i_a_t_e_d  _d_e_n_s_i_t_y
_m_a_t_r_i_x),  _u_s_u_a_l_l_y  _n_e_a_r  _t_h_e  _w_a_v_e_f_u_n_c_t_i_o_n _a_n_a_l_y_s_i_s _r_o_u_t_i_n_e_s
(_e._g., _t_h_e _p_e_r_e_n_n_i_a_l ``_M_u_l_l_i_k_e_n _p_o_p_u_l_a_t_i_o_n  _a_n_a_l_y_s_i_s''  _s_e_c_-
_t_i_o_n)  _o_r  _w_a_v_e_f_u_n_c_t_i_o_n  _p_r_o_p_e_r_t_i_e_s _s_e_c_t_i_o_n _o_f _t_h_e _c_o_d_e.  _I_f
_p_o_s_s_i_b_l_e, _r_e_s_t_r_i_c_t _t_h_e _m_o_d_i_f_i_c_a_t_i_o_n _o_f _y_o_u_r _E_S_S _s_o_u_r_c_e  _c_o_d_e
_t_o  _i_n_s_e_r_t_i_o_n  _o_f _a _s_i_n_g_l_e ``_C_A_L_L _R_U_N_N_B_O'' _s_t_a_t_e_m_e_n_t _a_t _s_o_m_e
_p_o_i_n_t _w_h_e_r_e _t_h_e _i_n_f_o_r_m_a_t_i_o_n _r_e_q_u_i_r_e_d  _f_o_r  _N_B_O  _a_n_a_l_y_s_i_s  _i_s
_k_n_o_w_n _t_o _b_e _a_v_a_i_l_a_b_l_e.

_C_h_e_c_k _c_a_r_e_f_u_l_l_y _f_o_r _p_o_s_s_i_b_l_e _c_o_n_f_l_i_c_t_s  _b_e_t_w_e_e_n  _t_h_e  _p_a_r_e_n_t
_E_S_S  _p_r_o_g_r_a_m  _a_n_d _t_h_e _N_B_O _p_r_o_g_r_a_m _i_n (_1) _f_u_n_c_t_i_o_n _o_r _s_u_b_r_o_u_-
_t_i_n_e _n_a_m_e_s, (_2) _C_O_M_M_O_N _b_l_o_c_k _n_a_m_e_s,  _a_n_d  (_3)  _l_o_g_i_c_a_l  _f_i_l_e
_a_s_s_i_g_n_m_e_n_t_s  (_L_F_N_s)  _f_o_r  _I/_O.   _N_B_O  _c_o_m_m_o_n _b_l_o_c_k _n_a_m_e_s _a_l_l
_b_e_g_i_n _w_i_t_h /_N_B.../, _a_n_d _d_e_f_a_u_l_t _L_F_N _a_s_s_i_g_n_m_e_n_t_s _a_r_e  _i_n  _t_h_e
_r_a_n_g_e  _3_1-_4_9.   (_D_u_p_l_i_c_a_t_e  _F_N _o_r _S_R _n_a_m_e_s _a_r_e _d_e_t_e_c_t_e_d _b_y _a
_l_i_n_k_e_r.)

_C_r_e_a_t_e _n_e_w _d_r_i_v_e_r (_i_n_t_e_r_f_a_c_i_n_g) _s_u_b_r_o_u_t_i_n_e_s _R_U_N_N_B_O,  _F_E_A_O_I_N,
_a_n_d  _D_E_L_S_C_F  _t_o  _p_e_r_f_o_r_m  _t_h_e _f_u_n_c_t_i_o_n_s _b_r_i_e_f_l_y _d_e_s_c_r_i_b_e_d _i_n
_S_e_c_t_i_o_n _C._1_1, _u_s_i_n_g _t_h_e _d_r_i_v_e_r_s _p_r_o_v_i_d_e_d _w_i_t_h _t_h_i_s _d_i_s_t_r_i_b_u_-
_t_i_o_n  _a_s _t_e_m_p_l_a_t_e_s _i_n_s_o_f_a_r _a_s _p_o_s_s_i_b_l_e.  _T_h_e _f_o_l_l_o_w_i_n_g _a_r_e _a
_f_e_w _h_e_l_p_f_u_l _h_i_n_t_s _f_o_r _e_a_c_h _d_r_i_v_e_r:

_T_h_e _R_U_N_N_B_O _r_o_u_t_i_n_e _s_h_o_u_l_d _b_e _r_e_l_a_t_i_v_e_l_y  _s_t_r_a_i_g_h_t_f_o_r_w_a_r_d  _t_o
_w_r_i_t_e,  _f_o_l_l_o_w_i_n_g _a_n _a_n_a_l_o_g_o_u_s _e_x_a_m_p_l_e _p_r_o_v_i_d_e_d _i_n _t_h_i_s _d_i_s_-
_t_r_i_b_u_t_i_o_n.  _N_o_t_e _t_h_a_t _y_o_u _c_a_n _s_i_m_p_l_y _o_m_i_t _t_h_e  _c_a_l_l_s  _t_o  _S_R
_N_B_O_E_A_N  _a_n_d  _S_R _D_E_L_S_C_F _f_r_o_m _R_U_N_N_B_O _i_f _y_o_u _d_o _n_o_t _p_l_a_n _t_o _u_s_e
_t_h_e _N_B_O _e_n_e_r_g_e_t_i_c _a_n_a_l_y_s_i_s (_f_o_r _e_x_a_m_p_l_e, _b_e_c_a_u_s_e _t_h_e  _D_E_L_S_C_F
_d_r_i_v_e_r _i_s _u_n_m_a_n_a_g_e_a_b_l_e).

_I_f _y_o_u_r _p_a_r_e_n_t _p_r_o_g_r_a_m _i_s _q_u_i_t_e _d_i_f_f_e_r_e_n_t _f_r_o_m _a_n_y _o_f  _t_h_o_s_e
_s_u_p_p_o_r_t_e_d  _b_y _t_h_i_s _d_i_s_t_r_i_b_u_t_i_o_n, _c_h_o_o_s_e _a_n _a_l_t_e_r_n_a_t_e _v_e_r_s_i_o_n
_n_u_m_b_e_r [_N_B_O_O_P_T(_1_0)], _a_n_d _c_a_r_e_f_u_l_l_y _c_o_n_s_i_d_e_r _s_t_e_p _4 _b_e_l_o_w.

_R_o_u_t_i_n_e _F_E_A_O_I_N _s_h_o_u_l_d _f_e_t_c_h _i_n_f_o_r_m_a_t_i_o_n _a_b_o_u_t _t_h_e _e_l_e_c_t_r_o_n_i_c
_w_a_v_e_f_u_n_c_t_i_o_n  _f_r_o_m _y_o_u_r _E_S_S _p_a_c_k_a_g_e _a_n_d _l_o_a_d _i_t _i_n_t_o _t_h_e _N_B_O
_C_O_M_M_O_N _b_l_o_c_k_s _a_n_d _F_I_L_E_4_8 _d_i_r_e_c_t _a_c_c_e_s_s _f_i_l_e.  _T_h_i_s  _r_e_q_u_i_r_e_s
_i_n_t_i_m_a_t_e  _k_n_o_w_l_e_d_g_e  _o_f  _w_h_e_r_e _t_h_e_s_e _i_t_e_m_s _a_r_e _s_t_o_r_e_d _i_n _t_h_e
_E_S_S _p_r_o_g_r_a_m, _s_o _t_h_e _F_E_A_O_I_N _e_x_a_m_p_l_e_s _o_f _t_h_e _d_i_s_t_r_i_b_u_t_i_o_n  _m_a_y
_p_r_o_v_i_d_e  _l_i_t_t_l_e  _d_i_r_e_c_t _g_u_i_d_a_n_c_e.  _S_e_e _S_e_c_t_i_o_n_s _C._3, _C._4 _f_o_r
_d_e_s_c_r_i_p_t_i_o_n _o_f _t_h_e _N_B_O _C_O_M_M_O_N _b_l_o_c_k_s _a_n_d _f_i_l_e _r_e_c_o_r_d_s  _w_h_i_c_h
_m_u_s_t _b_e _i_n_i_t_i_a_l_i_z_e_d _b_y _t_h_i_s _r_o_u_t_i_n_e.

_N_o_t_e _t_h_a_t _t_h_e _N_B_O _a_n_a_l_y_s_i_s _w_i_l_l _p_e_r_f_o_r_m _p_r_o_p_e_r_l_y _w_i_t_h_o_u_t _t_h_e
_i_n_f_o_r_m_a_t_i_o_n  _s_t_o_r_e_d  _o_n _l_o_g_i_c_a_l _r_e_c_o_r_d_s _2, _5, _9, _3_0, _3_1, _4_0,
_4_1, _a_n_d _5_0-_5_2 _o_f _t_h_e _d_i_r_e_c_t _a_c_c_e_s_s _f_i_l_e.  _I_f _i_n_f_o_r_m_a_t_i_o_n  _i_s
_n_o_t  _p_r_o_v_i_d_e_d  _o_n _t_h_e_s_e _r_e_c_o_r_d_s, _t_h_e _N_B_O _p_r_o_g_r_a_m _w_i_l_l _s_i_m_p_l_y
_s_h_u_t _o_f_f (_w_i_t_h _w_a_r_n_i_n_g_s) _a_n_y _r_e_q_u_e_s_t_e_d _k_e_y_w_o_r_d _o_p_t_i_o_n_s _w_h_i_c_h
_a_r_e  _t_h_e_r_e_b_y  _i_n_c_o_m_p_a_t_i_b_l_e.  _I_n _a_d_d_i_t_i_o_n, _t_h_e _o_v_e_r_l_a_p _m_a_t_r_i_x
_o_f _r_e_c_o_r_d _1_0 _n_e_e_d _n_o_t _b_e _p_r_o_v_i_d_e_d _i_f _t_h_e _i_n_p_u_t _b_a_s_i_s _s_e_t  _i_s
_o_r_t_h_o_g_o_n_a_l, _a_n_d _t_h_e _e_n_e_r_g_i_e_s _o_f _r_e_c_o_r_d _8 _a_r_e _n_o_t _r_e_q_u_i_r_e_d _i_f
_t_h_e _N_B_O _e_n_e_r_g_e_t_i_c _a_n_a_l_y_s_i_s _i_s _n_o_t _i_m_p_l_e_m_e_n_t_e_d _f_o_r  _y_o_u_r  _E_S_S



                       July 11, 1995





                          - 136 -


_p_a_c_k_a_g_e.
_C_r_e_a_t_i_n_g _r_o_u_t_i_n_e _D_E_L_S_C_F _w_i_l_l _r_e_q_u_i_r_e _i_n_t_i_m_a_t_e  _k_n_o_w_l_e_d_g_e  _o_f
_t_h_e  _S_C_F _r_o_u_t_i_n_e_s _i_n _t_h_e _p_a_r_e_n_t _E_S_S _p_r_o_g_r_a_m; _a_g_a_i_n, _v_e_r_s_i_o_n_s
_o_f _D_E_L_S_C_F _p_r_o_v_i_d_e_d _w_i_t_h _t_h_i_s _d_i_s_t_r_i_b_u_t_i_o_n  _m_a_y  _o_n_l_y  _b_e  _o_f
_m_i_n_i_m_a_l _a_s_s_i_s_t_a_n_c_e.  _A_s _d_e_s_c_r_i_b_e_d _i_n _S_e_c_t_i_o_n _C._1_1, _S_R _D_E_L_S_C_F
_i_s _r_e_s_p_o_n_s_i_b_l_e _f_o_r _p_r_o_v_i_d_i_n_g _a _m_o_d_i_f_i_e_d _A_O _d_e_n_s_i_t_y _m_a_t_r_i_x _t_o
_a_n _S_C_F _e_n_e_r_g_y _e_v_a_l_u_a_t_o_r (_o_n_e _p_a_s_s _t_h_r_o_u_g_h_t _t_h_e _S_C_F _r_o_u_t_i_n_e_s)
_a_n_d _r_e_t_u_r_n_i_n_g _t_h_i_s _n_e_w _e_n_e_r_g_y _t_o _t_h_e _N_B_O  _d_e_l_e_t_i_o_n  _r_o_u_t_i_n_e_s
_v_i_a  _t_h_e _F_I_L_E_4_8 _d_i_r_e_c_t _a_c_c_e_s_s _f_i_l_e.  _I_f _y_o_u _d_o _n_o_t _i_n_t_e_n_d _t_o
_e_m_p_l_o_y _t_h_e _N_B_O _e_n_e_r_g_e_t_i_c _a_n_a_l_y_s_i_s, _y_o_u _n_e_e_d _n_o_t _p_r_o_v_i_d_e _t_h_i_s
_r_o_u_t_i_n_e  _t_o  _t_h_e _N_B_O _p_r_o_g_r_a_m.  [_N_o_t_e _t_h_a_t _t_h_e _2_n_d-_o_r_d_e_r _p_e_r_-
_t_u_r_b_a_t_i_o_n _t_h_e_o_r_y _e_n_e_r_g_y _a_n_a_l_y_s_i_s _w_i_l_l _b_e _c_a_r_r_i_e_d  _o_u_t  (_p_r_o_-
_v_i_d_e_d  _t_h_e  _F_o_c_k  _m_a_t_r_i_x  _i_s  _a_v_a_i_l_a_b_l_e)  _e_v_e_n _i_f _y_o_u _d_o _n_o_t
_i_n_c_l_u_d_e _t_h_e _N_B_O_E_A_N _a_n_d _D_E_L_S_C_F _e_n_e_r_g_y _a_n_a_l_y_s_i_s _r_o_u_t_i_n_e_s.]

_I_n _a_d_d_i_t_i_o_n _t_o _t_h_e _e_x_p_l_i_c_i_t_l_y  _s_y_s_t_e_m-_d_e_p_e_n_d_e_n_t  _s_u_b_r_o_u_t_i_n_e_s
_R_U_N_N_B_O,  _F_E_A_O_I_N, _a_n_d _D_E_L_S_C_F, _t_h_e_r_e _a_r_e _a _f_e_w _r_o_u_t_i_n_e_s _w_i_t_h_i_n
_t_h_e _N_B_O _p_r_o_g_r_a_m _w_h_i_c_h  _c_a_n  _b_e  _c_o_n_s_i_d_e_r_e_d  #_I_q_u_a_s_i#_N-_s_y_s_t_e_m
_d_e_p_e_n_d_e_n_t,   _a_n_d  _m_i_g_h_t,  _t_h_e_r_e_f_o_r_e,  _r_e_q_u_i_r_e  _m_o_d_i_f_i_c_a_t_i_o_n.
_T_h_e_s_e _a_r_e _S_R _N_B_O_S_E_T (_S_e_c_t_i_o_n _C._5._2) _a_n_d _t_h_e  `_I_N_P'  _r_o_u_t_i_n_e_s
_N_B_O_I_N_P, _C_O_R_I_N_P, _C_H_S_I_N_P, _a_n_d _D_E_L_I_N_P (_S_e_c_t_i_o_n _C._9):

_S_R _N_B_O_S_E_T _a_s_s_i_g_n_s _t_h_e _l_o_g_i_c_a_l _f_i_l_e _n_u_m_b_e_r_s (_L_F_N_s)  _3_1-_4_9  _t_o
_b_e  _u_s_e_d  _b_y  _t_h_e _N_B_O _p_r_o_g_r_a_m.  _A_s _m_e_n_t_i_o_n_e_d _a_b_o_v_e, _i_f _t_h_e_s_e
_a_r_e _i_n _c_o_n_f_l_i_c_t _w_i_t_h _t_h_e _f_i_l_e_s _e_m_p_l_o_y_e_d _b_y  _t_h_e  _p_a_r_e_n_t  _E_S_S
_p_r_o_g_r_a_m,  _t_h_e _c_o_n_f_l_i_c_t_i_n_g _L_F_N_s _w_i_l_l _h_a_v_e _t_o _b_e _r_e_a_s_s_i_g_n_e_d _i_n
_t_h_i_s _s_u_b_r_o_u_t_i_n_e.

_T_h_e `_I_N_P' _r_o_u_t_i_n_e_s _m_a_y _h_a_v_e _t_o _b_e _m_o_d_i_f_i_e_d _a_c_c_o_r_d_i_n_g _t_o  _t_h_e
_m_a_n_n_e_r  _i_n _w_h_i_c_h _t_h_e _i_n_p_u_t _f_i_l_e _o_f _t_h_e _p_a_r_e_n_t _p_r_o_g_r_a_m _s_h_o_u_l_d
_b_e _p_r_o_c_e_s_s_e_d _b_y _t_h_e _N_B_O _p_r_o_g_r_a_m.  _M_o_r_e  _s_p_e_c_i_f_i_c_a_l_l_y,  _t_h_e_s_e
_r_o_u_t_i_n_e_s  _e_i_t_h_e_r  _r_e_w_i_n_d _t_h_e _i_n_p_u_t _f_i_l_e _b_e_f_o_r_e _s_e_a_r_c_h_i_n_g _f_o_r
_t_h_e_i_r _a_s_s_o_c_i_a_t_e_d _k_e_y_l_i_s_t _i_d_e_n_t_i_f_i_e_r, _o_r  _t_h_e_y  _s_i_m_p_l_y  _b_e_g_i_n
_s_e_a_r_c_h_i_n_g _t_h_e _i_n_p_u_t _f_i_l_e _s_e_q_u_e_n_t_i_a_l_l_y _a_t _t_h_e _p_o_i_n_t _w_h_e_r_e _t_h_e
_p_a_r_e_n_t _p_r_o_g_r_a_m _l_e_f_t _o_f_f, _d_e_p_e_n_d_i_n_g  _o_n  _t_h_e  _v_e_r_s_i_o_n  _n_u_m_b_e_r
_s_p_e_c_i_f_i_e_d  _i_n  _N_B_O_O_P_T(_1_0).   _B_e  _s_u_r_e _t_h_i_s _p_a_r_a_m_e_t_e_r _i_s _c_o_n_-
_s_i_s_t_e_n_t _w_i_t_h _t_h_e _w_a_y _y_o_u _w_i_s_h _t_o _m_o_d_i_f_y _t_h_e _E_S_S  _i_n_p_u_t  _f_i_l_e
_f_o_r _N_B_O _i_n_p_u_t.
_0_0_1_1_1_1_1_1_1_1_0_0// _0_1_1_1_0_0_0_0_1_1_1_0// _0_1_1_0_0_0_0_0_0_1_1_0//  _1_1_0_0_0_0_0_0_0_0_1_1//
_1_1_0_0_0_0_0_0_0_0_1_1//  _1_1_0_0_0_0_0_0_0_0_1_1// _1_1_0_0_0_0_0_0_0_0_1_1// _0_1_1_0_0_0_0_0_0_1_1_0//
_0_1_1_1_0_0_0_0_1_1_1_0// _0_0_1_1_1_1_1_1_1_1_0_0// _0_0_0_0_1_1_1_1_0_0_0_0//  _0_0_0_0_0_0_0_0_0_0_0_0//
_0_0_0_0_0_0_0_0_0_0_0_0//  _0_0_0_0_0_0_0_0_0_0_0_0// _0_0_0_0_0_0_0_0_0_0_0_0// _0_0_0_0_0_0_0_0_0_0_0_0//
_0_0_0_0_0_0_0_0_0_0_0_0// _0_0_0_0_0_0_0_0_0_0_0_0// _0_0_0_0_0_0_0_0_0_0_0_0//  _0_0_0_0_0_0_0_0_0_0_0_0//
_0_0_0_0_0_0_0_0_0_0_0_0//  _0_0_0_0_0_0_0_0_0_0_0_0// _0_0_0_0_0_0_0_0_0_0_0_0// _0_0_0_0_0_0_0_0_0_0_0_0//
_0_0_0_0_0_0_0_0_0_0_0_0// _0_0_0_0_0_0_0_0_0_0_0_0// _0_0_0_0_0_0_0_0_0_0_0_0// _0_0_0_0_0_0_0_0_0_0_0_0>>





#_H_S_e_c_t_i_o_n _D: _A_P_P_E_N_D_I_X#_N


#_B_D._1 _I_N_T_R_O_D_U_C_T_I_O_N#_N



                       July 11, 1995





                          - 137 -


_0 _T_h_i_s _A_p_p_e_n_d_i_x _c_o_n_t_a_i_n_s _s_y_s_t_e_m-_d_e_p_e_n_d_e_n_t _i_n_f_o_r_m_a_t_i_o_n  _a_b_o_u_t
_N_B_O  _i_n_p_u_t _a_n_d _s_o_u_r_c_e _c_o_d_e _f_o_r _t_h_e _E_S_S (_e_l_e_c_t_r_o_n_i_c _s_t_r_u_c_t_u_r_e
_s_y_s_t_e_m) _p_a_c_k_a_g_e_s _s_u_p_p_o_r_t_e_d _b_y _t_h_i_s _d_i_s_t_r_i_b_u_t_i_o_n.  _W_e  _a_s_s_u_m_e
_t_h_a_t  _t_h_e _u_s_e_r _h_a_s _b_a_s_i_c _f_a_m_i_l_i_a_r_i_t_y _w_i_t_h _t_h_e _E_S_S _p_r_o_g_r_a_m _o_f
_i_n_t_e_r_e_s_t.

_0 _T_h_e _A_p_p_e_n_d_i_x _i_s _o_r_g_a_n_i_z_e_d _a_c_c_o_r_d_i_n_g _t_o  _t_h_e  _E_S_S  _p_a_c_k_a_g_e_s
_s_u_p_p_o_r_t_e_d, _w_h_i_c_h _a_r_e _d_e_s_c_r_i_b_e_d _i_n _S_e_c_t_i_o_n_s _D._2-_D._7, _a_s _s_h_o_w_n
_b_e_l_o_w:


_0 _E_a_c_h _E_S_S _s_e_c_t_i_o_n _c_o_n_t_a_i_n_s _i_n_f_o_r_m_a_t_i_o_n _o_n:

_S_a_m_p_l_e _i_n_p_u_t _f_i_l_e _f_o_r _R_H_F/_3-_2_1_G _m_e_t_h_y_l_a_m_i_n_e

_N_B_O _p_r_o_g_r_a_m _i_n_s_t_a_l_l_a_t_i_o_n

_C_o_m_m_u_n_i_c_a_t_i_o_n _b_e_t_w_e_e_n _t_h_e _N_B_O _d_r_i_v_e_r_s _a_n_d _t_h_e _E_S_S _p_r_o_g_r_a_m

_0 _F_o_r _m_o_s_t _u_s_e_r_s, _o_n_l_y _t_h_e _f_i_r_s_t _s_e_c_t_i_o_n(_s) _o_n _s_a_m_p_l_e  _i_n_p_u_t
_f_i_l_e _w_i_l_l _b_e _r_e_q_u_i_r_e_d _r_e_a_d_i_n_g.  _F_o_r _t_h_e _p_r_o_g_r_a_m_m_e_r _r_e_s_p_o_n_s_i_-
_b_l_e _f_o_r _a_t_t_a_c_h_i_n_g _t_h_e _N_B_O _p_r_o_g_r_a_m _t_o  _a_n  _E_S_S  _p_a_c_k_a_g_e,  _t_h_e
_f_i_n_a_l  _s_e_c_t_i_o_n  _o_n _N_B_O _d_r_i_v_e_r_s _w_i_l_l _b_e _i_m_p_o_r_t_a_n_t _o_n_l_y _i_f _t_h_e
_a_v_a_i_l_a_b_l_e  _E_S_S  _v_e_r_s_i_o_n  _d_i_f_f_e_r_s  _s_i_g_n_i_f_i_c_a_n_t_l_y  _f_r_o_m   _t_h_a_t
_a_s_s_u_m_e_d _i_n _t_h_e _i_n_s_t_a_l_l_a_t_i_o_n _i_n_s_t_r_u_c_t_i_o_n_s.

_0 _I_n _t_h_e _A_p_p_e_n_d_i_x _w_e _u_s_e ``_S_R'' _a_n_d ``_F_N'' _t_o _d_e_n_o_t_e _s_u_b_r_o_u_-
_t_i_n_e_s _a_n_d _f_u_n_c_t_i_o_n_s, _r_e_s_p_e_c_t_i_v_e_l_y.

#_B_D._2 _G_A_U_S_S_I_A_N _8_8 _V_E_R_S_I_O_N#_N

#_I_D._2._1 _G_A_U_S_S_I_A_N _8_8 _s_a_m_p_l_e _i_n_p_u_t#_N

_0 _A _s_a_m_p_l_e _G_A_U_S_S_I_A_N _8_8 _i_n_p_u_t _f_i_l_e _t_o  _r_e_c_r_e_a_t_e  _t_h_e  _d_e_f_a_u_l_t
_m_e_t_h_y_l_a_m_i_n_e  (_R_H_F/_3-_2_1_G  _a_t _P_o_p_l_e-_G_o_r_d_o_n _i_d_e_a_l_i_z_e_d _g_e_o_m_e_t_r_y)
_o_u_t_p_u_t _d_i_s_p_l_a_y_e_d _i_n _S_e_c_t_i_o_n _A._3 _i_s _s_h_o_w_n _b_e_l_o_w:

# _R_H_F/_3-_2_1_G

_M_e_t_h_y_l_a_m_i_n_e..._R_H_F/_3-_2_1_G//_P_o_p_l_e-_G_o_r_d_o_n _s_t_a_n_d_a_r_d _g_e_o_m_e_t_r_y

 _0   _1
 _C
 _N   _1   _C_N
 _H   _1   _C_H   _2   _t_e_t
 _H   _1   _C_H   _2   _t_e_t   _3   _1_2_0.  _0
 _H   _1   _C_H   _2   _t_e_t   _3   _2_4_0.  _0
 _H   _2   _N_H   _1   _t_e_t   _3    _6_0.  _0
 _H   _2   _N_H   _1   _t_e_t   _3   _3_0_0.  _0

 _C_N        _1._4_7
 _C_H        _1._0_9
 _N_H        _1._0_1
 _t_e_t     _1_0_9._4_7_1_2



                       July 11, 1995





                          - 138 -


$_N_B_O  $_E_N_D
 #_T

     @seg


     0 #NThe keylists  of  the  NBO  program  should  always
     appear  at the bottom of the GAUSSIAN 88 input file and
     should be ordered: $NBO, $CORE, $CHOOSE, $DEL.  NBO job
     options are selected by inserting their associated key-
     words (Section B.2) into the  $NBO  keylist.   All  NBO
     keywords are applicable to the electronic wavefunctions
     computed by the GAUSSIAN 88 programs.

     0 If the NBO program encounters the  end-of-file  while
     searching  for a keylist, the input file is rewound and
     the search for the keylist is continued.  This is  par-
     ticularly  useful  for jobs which call the NBO analysis
     several times.  For example, an  MP2  calculation  with
     the  GAUSSIAN  88 option DENSITY=ALL causes Link 601 to
     loop over three densities (SCF,  Rho2,  and  MP2),  and
     hence, the NBO analysis is called three times, once for
     each density.  A single $NBO  keylist  (and  $CORE  and
     $CHOOSE  keylists)  will suffice as input for all three
     analyses.  Alternatively, separate $NBO  keylists,  one
     for  each  density,  could be inserted at the bottom of
     the GAUSSIAN 88 input file.




                          - 138 -
77777777777777777777777777777777     0 The IOp parameters 40-43 of Link 601 exert additional
     control over the NBO program, as listed below:


     For example, to restrict the NBO output to the  Natural
     Population  analysis (NPA) only, set IOp(40) to minus 1
     in all Link 601 entries of a GAUSSIAN  88  non-standard
     route, as shown below:

     #T     6/40=-1/1;

     #NBy default, the NBO analysis will be performed, read-
     ing  keywords from the $NBO keylist [IOp(40)=0], on the
     density  matrix  for  the  current  wavefunction.   The
     DIPOLE  and  RESONANCE keywords are generally activated
     through the $NBO keylist rather than via the IOp param-
     eters.




                          - 138 -
7777777777777777777777     #ID.2.2 NBO energetic analysis#N

     0 Due to the overlay structure of the GAUSSIAN 88  pro-
     grams, a non-standard route must be employed to perform
     the NBO energetic analysis.  The following table  lists
     and describes the tasks of the GAUSSIAN 88 links in the
     order that they appear in the non-standard route:

     #IDESCRIPTION#N

     Perform the normal NBO  analysis,  storing  information
     about  the  NBOs  for the NBO energetic analysis on the
     FILE48 direct access file.

     Read the next deletion listed in the $DEL keylist.   If
     there  are  no  more  deletions, move to the next link.
     Otherwise, compute the modified density  matrix,  store
     it  on  the read-write files, and skip the next link in
     the non-standard route.

     Finish GAUSSIAN 88 execution.

     Using the modified density matrix, compute the deletion
     energy  by a single pass through the SCF energy evalua-
     tor.  Store  the  deletion  energy  on  the  read-write
     files.

     Read the deletion energy from the read-write files  and
     complete  the  energetic  analysis.  Step backwards, in
     the non-standard route, three links.


     0 The following is a GAUSSIAN 88 input file  that  will
     generate,  in  addition  to the default NBO output, the
     NLMO  (Section  B.6.2),  the  dipole  moment   (Section
     B.6.3), and the NBO energetic (Section B.6.10) analyses
     of methylamine:

#  NONSTD  1//1;  2//2;   3/5=5,11=1,25=14,30=1/1,2,3,11,14;
4/7=1/1;   5//1;   6/7=2,8=2,9=2,10=2,19=1/1;   6/40=2/1(1);
99/5=1,9=1/99; 5/7=1,13=1/1; 6/40=3/1(-3);

Methylamine...RHF/3-21G//Pople-Gordon standard geometry

 0   1
 C
 N   1   CN
 H   1   CH   2   tet
 H   1   CH   2   tet   3   120.  0
 H   1   CH   2   tet   3   240.  0
 H   2   NH   1   tet   3    60.  0
 H   2   NH   1   tet   3   300.  0

 CN        1.47



                       July 11, 1995





                          - 139 -


CH        1.09
 NH        1.01
 tet     109.4712

$NBO  NLMO  DIPOLE  $END $DEL  NOSTAR
      ZERO 2 ATOM BLOCKS   4  BY  3
                           1  3  4  5
                           2  6  7
                           3  BY  4
                           2  6  7
                           1  3  4  5 $END
 #T

@seg


0 #NNote that for the GAUSSIAN 88 version of  the  NBO  pro-
gram,  each deletion in the $DEL keylist must begin on a new
line of the input file (the first deletion  can  follow  the
``$DEL''  keylist identifier, as shown above).  The ``$END''
keylist terminator must also appear on its own line.




                          - 139 -
77777777777777777777777777#ID.2.3 Geometry reoptimization with NBO deletions#N

0 The structural effects of electron delocalization  can  be
examined  by  coupling  the  NBO  energetic  analysis to the
Fletcher-Powell (numerical) geometry  optimization  routines
of the GAUSSIAN 88 package.  The following GAUSSIAN 88 input
file  will  reoptimize  selected  internal  coordinates   of
RHF/3-21G   methylamine   in   the  absence  of  its  strong
#In#N#dN#u7arr gma  #u*#d#d#> C C     Run the NBO ener-
getic analysis.  C
      If(IOp(40).ge.2) then
        IDens = 0                  ! SCF density  for  dele-
tion runs
        IOp(41) = IDens
        Call RunNBO(Core,NGot,IOp,IContr)
        go to 999
      endIf C C     <<< End of  first  NBO  insert  >>  C  C
Put density matrices first.  C
      IPA = IEnd1 + 1

      .
      .
      .




                          - 140 -
77777777777777777777777777777777777777777          Call
ElEner(IOut,ISelfE,SCFDen,ISCF,IROHF,NAE,NBE,NBasis,
     $      Core(IPA),Core(IV),MDV) C C     <<< Beginning of
second NBO insert >>> C C     Run the NBO analysis.  C
          If(IOp(40).ne.-2) then
            IOp(41) = IDens
            Call RunNBO(Core,NGot,IOp,IContr)
          endIf C C     <<< End of second NBO insert >>> C
        else if(IDens1.eq.IDSt.and.IDens1.eq.IDEnd) then

      .
      .
      .

      Call
PrtPol(IOut,ISCF,IRotat,IRwDip,NAE,NBE,NBasis,NTT,
     $
Core(IExPol),Core(ICMO),Core(IT),Core(IEV),Core(IDip))  C  C
<<< Beginning of third NBO insert >>> C C     The  following
line  has  been changed from "Call ChainX(0)" in C     order
to exit the NBO deletion loop after the deletions are  done:
C
  999 Call ChainX(IContr) C  C      <<<  End  of  third  NBO
insert >>> C
      Return
      End
 #T

@seg


0  #NThe  first  NBO  insert  initiates  the  NBO  energetic
analysis  of  SCF  wavefunctions.   The  second  insert lies
within a loop over densities, and thus, the NBO  program  is
called  once  for each density matrix analyzed by this link.
The third insert allows the NBO energetic analysis  to  exit
from the loop in the non-standard route.

The NBO program installation should continue as discussed in
Section A.2.




                          - 140 -
777777777777777777777777777777777777777777777#ID.2.5 NBO communication with GAUSSIAN 88#N

0 The NBO driver routines (RUNNBO,  FEAOIN,  DELSCF)  access
the  following  GAUSSIAN  88 routines, read-write files, and
COMMON blocks:

#_GAUSSIAN 88 routines:#/#T

    SR CharPn(IString)
    SR DENGET(IOut,IODens,IMeth,LenDen,GotIt,P)
    FN ILSW(IOPER,WHERE,WHAT)
    FN InToWP(Nints)
    FN ITqry(Ifile)
    SR TRead(IARN,X,M,N,MM,NN,K)
    SR TWrite(IARN,X,M,N,MM,NN,K)

#N#_GAUSSIAN 88 read-write files:#/


#_GAUSSIAN 88 COMMON blocks:#/#T

    COMMON/MOL/NATOM,ICHARG,MULTIP,NAE,NBE,NE,NBASIS,IAN(401),
   +           ATMCHG(400),C(1200)
    COMMON/LP2/NLP(1600),CLP(1600),ZLP(1600),KFIRST(400,5),
   +  KLAST(400,5),LMAX(400),LPSKIP(400),NFroz(400)
    COMMON/B/EXX(6000),C1(6000),C2(6000),C3(6000),X(2000),Y(2000),
   +
Z(2000),JAN(2000),SHELLA(2000),SHELLN(2000),SHELLT(2000),
   +     SHELLC(2000),AOS(2000),AON(2000),NSHELL,MAXTYP
    INTEGER SHELLA,SHELLN,SHELLT,SHELLC,SHLADF,AOS,AON
    DIMENSION C4(2000),SHLADF(2000)
    EQUIVALENCE(C4(1),C3(2001)),(SHLADF(1),C3(4001))
 #N #BD.3 GAUSSIAN 86 VERSION#N

#ID.3.1 GAUSSIAN 86 sample input#N

0 See Section D.2.1.  Note that the NBO  IOp  parameters  of
Link  601  are  set to 40-43 (changed from 20-23 in previous
distributions of the NBO program).

#ID.3.2 NBO energetic analysis#N

0 See Section D.2.2.

#ID.3.3 Geometry reoptimization with NBO deletions#N

0 See Section D.2.3.




                          - 140 -
7777777777777777777777777777777777777777777777777777#ID.3.4 NBO program installation#N

0 The NBO interfacing (driver)  routines  provided  in  this
distribution  were  written  for  the  Revision C version of
GAUSSIAN 86, dated 30-APR-1986.   Section  D.3.5  lists  the
GAUSSIAN  86  dependent  elements of the NBO driver routines
that may need slight modification for other versions of  the
GAUSSIAN 86 programs.

0 Two modifications to SR MulDrv of Link 601 are required to
run the NBO analysis:

*Deck MulDrv
      Subroutine MulDrv(Core)
      .
      .
      .

      If(NGot.lt.IEnd1) Write(IOut,2002) IEnd1, NGot
      Len2 = (NGot-I2A+1)/NTT C C     <<< Beginning of first
NBO insert >>> C
      IF(IOp(40).GE.2.OR.IOp(41).NE.0) GO TO 999 C C     <<<
End  of first NBO insert >>> C C     Do population analysis.
C
      CALL
MULPOP(MaxAtm,IOP,IROHF,NATOMS,ICHARG,MULTIP,NAE,NBE,NBASIS,

      .
      .
      .

      Call
PrtPol(IOut,ISCF,IRotat,IRwDip,NAE,NBE,NBasis,NTT,
     $
Core(IExPol),Core(ICMO),Core(IT),Core(IEV),Core(IDip))  C  C
<<< Beginning of second NBO insert >>> C
  999 Call GetSCM(-1,Core(1),NGot,3HNBO,0)
      Call RunNBO(Core,NGot,IOp,IContr) C C     The  follow-
ing  line  has  been  changed from "999 Call ChainX(0)" in C
order to exit the NBO deletion loop after deletions are com-
plete.  C
      Call ChainX(IContr) C C      <<<  End  of  second  NBO
insert >>> C
      Return
      End
 #T

@seg




                          - 140 -
777777777777777777777777777777777777777777777777777770 #NThe first NBO insert allows Link 601 to by-pass the Mul-
liken  Population  and  electric moment analysis routines if
the NBO energetic analysis is to be performed or if a corre-
lated  wavefunction  is  being  analyzed.  The second insert
requests all available memory be allocated for the NBO  pro-
gram  and initiates the NBO analysis.  Note that the call to
SR ChainX has been altered from the original code.

The NBO program installation should continue as discussed in
Section A.2.




                          - 140 -
777777777777777#ID.3.5 NBO communication with GAUSSIAN 86#N

0 The NBO driver routines (RUNNBO,  FEAOIN,  DELSCF)  access
the  following  GAUSSIAN  86 routines, read-write files, and
COMMON blocks:

#_GAUSSIAN 86 routines:#/#T

    SR CharPn(IString)
    FN ILSW(IOPER,WHERE,WHAT)
    FN InToWP(Nints)
    FN ITqry(Ifile)
    SR TRead(IARN,X,M,N,MM,NN,K)
    SR TWrite(IARN,X,M,N,MM,NN,K)

#N#_GAUSSIAN 86 read-write files:#/


#_GAUSSIAN 86 COMMON blocks:#/#T

    COMMON/MOL/NATOM,ICHARG,MULTIP,NAE,NBE,NE,NBASIS,IAN(401),
   +           ATMCHG(400),C(1200)
    COMMON/LP2/NLP(1600),CLP(1600),ZLP(1600),KFIRST(400,5),
   +  KLAST(400,5),LMAX(400),LPSKIP(400),NFroz(400)
    COMMON/B/EXX(1200),C1(1200),C2(1200),C3(1200),X(400),Y(400),
   +
Z(400),JAN(400),SHELLA(400),SHELLN(400),SHELLT(400),
   +     SHELLC(400),AOS(400),AON(400),NSHELL,MAXTYP
    INTEGER SHELLA,SHELLN,SHELLT,SHELLC,SHLADF,AOS,AON
    DIMENSION C4(400),SHLADF(400)
    EQUIVALENCE(C4(1),C3(401)),(SHLADF(1),C3(801))
 #N #BD.4 GAUSSIAN 82 VERSION#N

#ID.4.1 GAUSSIAN 82 sample input#N

0 See Section D.2.1.  Note that the NBO  IOp  parameters  of
Link  601  are  set to 40-43 (changed from 20-23 in previous
distributions of the NBO program).

#ID.4.2 NBO energetic analysis#N

0 See Section D.2.2.

#ID.4.3 Geometry reoptimization with NBO deletions#N

0 See Section D.2.3.




                          - 140 -
777777777777777777777777777777777777777777777777777#ID.4.4 NBO program installation#N

0 The NBO interfacing (driver)  routines  provided  in  this
distribution  were  written  for  the  Revision H version of
GAUSSIAN 82, dated 28-NOV-1983.   Section  D.4.5  lists  the
GAUSSIAN  82  dependent  elements of the NBO driver routines
that may need slight modification for other versions of  the
GAUSSIAN 82 programs.

0 Two modifications to SR MulDrv of Link 601 are required to
run the NBO analysis:

*Deck MulDrv
      Subroutine MulDrv(Core)

      .
      .
      .

      IF(IPRINT.NE.0)
     $WRITE(IOUT,2001)I1,I2,I3,I4,I5,I6,I7,I8,I9,I10,IEND  C
C     <<< Beginning of first NBO insert >>> C C     The fol-
lowing line has been changed from "CALL GETSCM(IEND,...)", C
in order to ask for all available memory.  C
      CALL GETSCM(-1,CORE(1),JJJMEM,6HMULDRV,0) C
      IF(IOP(40).GE.2.OR.IOP(41).NE.0) GO TO 100 C C     <<<
End  of  first  NBO  insert  >>>  C  C     DO THE POPULATION
ANALYSIS.
      CALL
MULPOP(IOP,NATOMS,ICHARG,MULTIP,NAE,NBE,NBASIS,IAN,AtmChg,
     $  C,Core(I1),CORE(I2),CORE(I3),CORE(I4),CORE(I5),
     $  CORE(I6),CORE(I7),CORE(I8),CORE(I9),CORE(I10))  C  C
<<< Beginning of second NBO insert >>> C
  100 CALL RUNNBO(CORE,JJJMEM,IOP,ICONTR) C C      The  fol-
lowing  line  has  been  changed  from "CALL CHAINX(0)" in C
order to exit the NBO deletion loop after deletions are com-
plete.  C
      CALL CHAINX(ICONTR) C C      <<<  End  of  second  NBO
insert >>> C
      RETURN
      END
 #T

@seg




                          - 140 -
77777777777777777777777777777777777777777777777770 #NThe first NBO insert allows Link 601 to by-pass the Mul-
liken  Population  analysis  routines  if  the NBO energetic
analysis is to be performed or if a correlated  wavefunction
is  being  analyzed.   The  second  insert initiates the NBO
analysis.  Note that the calls to routines GETSCM and CHAINX
have been altered from the original code.

The NBO program installation should continue as discussed in
Section A.2.




                          - 140 -
77777777777777#ID.4.5 NBO communication with GAUSSIAN 82#N

0 The NBO driver routines (RUNNBO,  FEAOIN,  DELSCF)  access
the  following  GAUSSIAN  82 routines, read-write files, and
COMMON blocks:

#_GAUSSIAN 82 routines:#/#T

    SR CharPn(IString)
    FN ILSW(IOPER,WHERE,WHAT)
    FN InToWP(Nints)
    FN ITqry(Ifile)
    SR TRead(IARN,X,M,N,MM,NN,K)
    SR TWrite(IARN,X,M,N,MM,NN,K)

#N#_GAUSSIAN 82 read-write files:#/


#_GAUSSIAN 82 COMMON blocks:#/#T

    COMMON/MOL/NATOM,ICHARG,MULTIP,NAE,NBE,NE,NBASIS,IAN(101),
   +           ATMCHG(100),C(300)
    COMMON/LP2/NLP(400),CLP(400),ZLP(400),KFIRST(100,5),
   +  KLAST(100,5),LMAX(100),LPSKIP(100),NFroz(100)
    COMMON/B/EXX(240),C1(240),C2(240),C3(240),X(80),Y(80),
   +     Z(80),JAN(80),SHELLA(80),SHELLN(80),SHELLT(80),
   +     SHELLC(80),AOS(80),AON(80),NSHELL,MAXTYP
    INTEGER SHELLA,SHELLN,SHELLT,SHELLC,SHLADF,AOS,AON
    DIMENSION C4(80),SHLADF(80)
    EQUIVALENCE(C4(1),C3(81)),(SHLADF(1),C3(161))
 #N #BD.5 GAMESS VERSION#N

#ID.5.1 GAMESS sample input#N

0 A sample GAMESS input file to recreate the default  methy-
lamine (RHF/3-21G at Pople-Gordon idealized geometry) output
displayed in Section A.3 is shown below:

 $CONTRL  SCFTYP=RHF  RUNTYP=ENERGY  $END
 $DATA    Methylamine...RHF/3-21G//Pople-Gordon     standard
geometry CS       0

Carbon          6.          -0.713673              -0.014253
0.000000
    1   SV    3  N21

Nitrogen        7.           0.749817               0.123940
0.000000
    1   SV    3  N21

Hydrogen        1.          -0.978788              -1.071520
0.000000
    1   SV    3  N21




                       July 11, 1995





                          - 141 -


Hydrogen        1.          -1.123702               0.463146
-0.889982
    1   SV    3  N21

Hydrogen        1.           1.129752              -0.318420
0.824662
    1   SV    3  N21

 $END
 $GUESS  GUESS=EXTGUESS  $END
 $NBO  $END
 #T

@seg


0 #NNBO job options are selected by inserting their  associ-
ated  keywords (Section B.2) into the $NBO keylist.  All NBO
keywords are applicable to the electronic wavefunctions com-
puted by GAMESS.

0 The following is a modified GAMESS input  file  that  will
generate,  in  addition  to the default NBO output, the NLMO
(Section B.6.2), the dipole moment (Section B.6.3), and  the
NBO energetic (Section B.6.10) analyses of methylamine:

 $CONTRL  SCFTYP=RHF  RUNTYP=ENERGY  $END
 $DATA    Methylamine...RHF/3-21G//Pople-Gordon     standard
geometry CS       0

Carbon          6.          -0.713673              -0.014253
0.000000
    1   SV    3  N21

Nitrogen        7.           0.749817               0.123940
0.000000
    1   SV    3  N21

Hydrogen        1.          -0.978788              -1.071520
0.000000
    1   SV    3  N21

Hydrogen        1.          -1.123702               0.463146
-0.889982
    1   SV    3  N21

Hydrogen        1.           1.129752              -0.318420
0.824662
    1   SV    3  N21

 $END
 $GUESS  GUESS=EXTGUESS  $END
 $NBO  NLMO  DIPOLE  $END
 $DEL  NOSTAR



                       July 11, 1995





                          - 142 -


ZERO 2 ATOM BLOCKS     4  BY  3
                              1  3  4  5
                              2  6  7
                              3  BY  4
                              2  6  7
                              1  3  4  5



                          - 142 -
7777777777 $END
 #T

@seg


0 #NIn general, the $NBO, $CORE, $CHOOSE, and $DEL  keylists
can  be  inserted in any order within the GAMESS input file;
the NBO program rewinds the input file each time it searches
for a keylist.




                          - 142 -
777777777777777#ID.5.2 NBO program installation#N

0 The NBO interfacing (driver)  routines  provided  in  this
distribution  were  written  for the GAMESS program dated 6-
DEC-1989.  Section D.5.3 lists the GAMESS dependent elements
of the NBO driver routines that may need slight modification
for other versions of the GAMESS program.

0 Only one command line is added to the GAMESS  source  code
to  run  the NBO analysis.  A call (``IF(RHO) CALL RUNNBO'')
should be inserted at the end of the GAMESS properties pack-
age (SR HFPROP in module PRPLIB), as shown below:

C*MODULE PRPLIB  *DECK HFPROP
      SUBROUTINE HFPROP(SCFTYP)

                 .
                 .
                 .

C C     ----- SELECT DESIRED ELECTROSTATIC PROPERTIES  -----
C
      CALL PRSELC(SCFTYP) C
      WRITE(IW,FMT='('' ...... END  OF  PROPERTY  EVALUATION
......'')')
      CALL TIMIT(1) C C     <<< BEGINNING OF NBO INSERT  >>>
C
      IF(RHO) CALL RUNNBO C C     <<< END OF NBO INSERT  >>>
C
      RETURN
      END
 #T

@seg


0 #NIf the density matrix is available (RHO =  .TRUE.),  the
NBO  analysis  is performed each time the properties package
is called within GAMESS.  For example, the NBO  analysis  of
the computed wavefunction will be performed for every single
point calculation and for both the initial and final  points
of  a  geometry  optimization.   The  NBO output will appear
immediately after the Mulliken Population Analysis  and  the
electric properties in the GAMESS output file.

0 The NBO program installation should continue as  discussed



                          - 142 -
77777777777777777777777777777777777777777777777777in Section A.2.
#ID.5.3 NBO communication with GAMESS#N

0 The NBO driver routines (RUNNBO,  FEAOIN,  DELSCF)  access
the  following  GAMESS  routines,  records of the dictionary
file, and COMMON blocks:

#_GAMESS routines:#T#/

    SR DAREAD(IDAF,IODA,V,LEN,NREC,NAV)
    FN ENUC(N,Z,C)
    ENTRY GOTFM(IPAR)
    SR HSTAR(D,F,XX,IX,NINTMX,IA,NOPK)
    SR HSTARU(DA,FA,DB,FB,XX,IX,XP,XK,IXPK,NINTMX,IA,NOPK)
    SR SYMH(F,H,IA)
    FN TRACEP(A,B,N)
    SR VADD(A,I,B,J,C,K,N)
    ENTRY VALFM(IPAR)

#_#NGAMESS dictionary file:#/


#_#NGAMESS COMMON blocks:#T#/

    PARAMETER (MXGTOT=5000, MXSH=1000, MXATM=50)
    COMMON                     /ECP2                       /
CLP(400),ZLP(400),NLP(400),KFIRST(MXATM,6),
   +
KLAST(MXATM,6),LMAX(MXATM),LPSKIP(MXATM),
   +                IZCORE(MXATM)
    COMMON /FMCOM / CORE(1)
    COMMON                     /INFOA                      /
NAT,ICH,MUL,NUM,NX,NE,NA,NB,ZAN(MXATM),C(3,MXATM)
    COMMON /INTFIL/ NINTMX,NHEX,NTUPL,PACK2E,INTG76
    COMMON /IOFILE/ IR,IW,IP,IS,IPK,IDAF,NAV,IODA(99)
    COMMON                     /NSHEL                      /
EX(MXGTOT),CS(MXGTOT),CP(MXGTOT),CD(MXGTOT),
   +
KSTART(MXSH),KATOM(MXSH),KTYPE(MXSH),KNG(MXSH),
   +                KLOC(MXSH),KMIN(MXSH),KMAX(MXSH),NSHELL
    COMMON /OUTPUT/ NPRINT,ITOL,ICUT,NORMF,NORMP,NOPK
    COMMON /RUNLAB/ TITLE(10),A(MXATM),B(MXATM),BFLAB(2047)
    COMMON /SCFOPT/ SCFTYP,BLKTYP,MAXIT,MCONV,NCONV,NPUNCH



                          - 142 -
77777777777777777777777777777777777777777777777    COMMON /XYZPRP/ X(3)
#BD.6 HONDO VERSION#N

#ID.6.1 HONDO sample input#N

0 A sample HONDO input file to recreate the  default  methy-
lamine (RHF/3-21G at Pople-Gordon idealized geometry) output
displayed in Section A.3 is shown below:

 $CNTRL  RUNFLG=0  $END
 $BASIS    Methylamine...RHF/3-21G//Pople-Gordon    standard
geometry
    0    0   15    1  N21 CS       0

Carbon          6.          -0.713673              -0.014253
0.000000 Nitrogen     7.        0.749817            0.123940
0.000000 Hydrogen     1.       -0.978788           -1.071520
0.000000 Hydrogen     1.       -1.123702            0.463146
-0.889982  Hydrogen       1.          1.129752             -
0.318420            0.824662
 $END
 $GUESS  NGUESS=4  $END
 $INTGRL  $END
 $WFN  WFNFLG=0  $END
 $SCF  NCO=9  $END
 $NBO  $END
 #T

@seg


0 #NNBO job options are selected by inserting their  associ-
ated  keywords (Section B.2) into the $NBO keylist.  All NBO
keywords are applicable to the electronic wavefunctions com-
puted by HONDO.

0 The following is a modified HONDO  input  file  that  will
generate,  in  addition  to the default NBO output, the NLMO
(Section B.6.2), the dipole moment (Section B.6.3), and  the
NBO energetic (Section B.6.10) analyses of methylamine:

 $CNTRL  RUNFLG=0  $END
 $BASIS    Methylamine...RHF/3-21G//Pople-Gordon    standard
geometry
    0    0   15    1  N21 CS       0

Carbon          6.          -0.713673              -0.014253
0.000000 Nitrogen     7.        0.749817            0.123940
0.000000 Hydrogen     1.       -0.978788           -1.071520
0.000000 Hydrogen     1.       -1.123702            0.463146
-0.889982  Hydrogen       1.          1.129752             -
0.318420            0.824662
 $END
 $GUESS  NGUESS=4  $END



                       July 11, 1995





                          - 143 -


$INTGRL  $END
 $WFN  WFNFLG=0  $END
 $SCF  NCO=9  $END
 $NBO  NLMO  DIPOLE  $END
 $DEL  NOSTAR
       ZERO 2 ATOM BLOCKS     4  BY  3
                              1  3  4  5
                              2  6  7
                              3  BY  4
                              2  6  7
                              1  3  4  5



                          - 143 -
777777777777777 $END
 #T

@seg


0 #NIn general, the $NBO, $CORE, $CHOOSE, and $DEL  keylists
can  be  inserted  in any order within the HONDO input file;
the NBO program rewinds the input file each time it searches
for a keylist.




                          - 143 -
777777777777777#ID.6.2 NBO program installation#N

0 The NBO interfacing (driver)  routines  provided  in  this
distribution  were written for HONDO 7.0, dated 18-JAN-1988.
Section D.6.3 lists the HONDO dependent elements of the  NBO
driver  routines that may need slight modification for other
versions of the HONDO program.

0 Only one command line is added to the HONDO source code to
run  the  NBO  analysis.  A call (``CALL RUNNBO'') should be
inserted at the end of  the  HONDO  properties  package  (SR
PROPTY in module PRP), as shown below:

      SUBROUTINE PROPTY

      .
      .
      .

C C     ----- ELECTRON AND SPIN DENSITIES ----- C
      IF(NODEN.EQ.0) CALL ELDENS C C      <<<  BEGINNING  OF
NBO INSERT >>> C
      CALL RUNNBO C C     <<< END OF NBO INSERT >>> C
      NCALL=0
      IF(SOME) NCALL=1
      CALL TIMIT(NCALL)
      RETURN

      .
      .
      .

      END
 #T

@seg


0 #NThe NBO analysis is performed each time  the  properties
package  is  called  within  HONDO.   For  example,  the NBO
analysis of the  computed  wavefunction  will  be  performed
(unless  NOPROP=1  in the $CONTRL namelist) for every single
point calculation, for each point on a scan of  a  potential
energy surface, and for both the initial and final points of
a geometry optimization.  The NBO output will appear immedi-
ately  after  the Mulliken Population Analysis and the elec-
tric properties in the HONDO output file.

0 The NBO program installation should continue as  discussed



                          - 143 -
77777777777777777777777777777777777777777777777777777in Section A.2.
#ID.6.3 NBO communication with HONDO#N

0 The NBO driver routines (RUNNBO,  FEAOIN,  DELSCF)  access
the  following  HONDO  routines,  records  of the dictionary
file, and COMMON blocks:

#_HONDO routines:#T#/

    SR DAREAD(IDAF,IODA,IX,NX,IDAR)
    SR DIPAMS(BMASS,NCALL,NCODE,SOME)
    FN DOTTRI(A,B,N)
    FN ENUC(N,Z,C)
    SR HSTAR(D,F,XX,IX,NINTMX,IA,NOPK)
    SR HSTARU(DA,FA,DB,FB,XX,IX,XP,XK,IXPK,NINTMX,IA,NOPK)
    SR SYMFCK(F,H,IA)

#_#NHONDO dictionary file:#/


#_#NHONDO COMMON blocks:#T#/

    COMMON/IJPAIR/IA(1)
    COMMON/INFOA/NAT,ICH,MUL,NUM,NX,NE,NA,NB,ZAN(50),C(3,50)
    COMMON/INTFIL/NOPK,NOK,NOSQUR,NINTMX,NHEX,NTUPL,PACK2E
    COMMON/IOFILE/IR,IW,IP,IJK,IPK,IDAF,NAV,IODA(99)
    COMMON/MEMORY/MAXCOR,MAXLCM
    COMMON/MOLNUC/NUC(50)
    COMMON/NSHEL/EX(440),CS(440),CP(440),CD(440),CF(440),CG(440),
   +             KSTART(120),KATOM(120),KTYPE(120),KNG(120),
   +             KLOC(120),KMIN(120),KMAX(120),NSHELL
    COMMON/RUNLAB/TITLE(10),ANAM(50),BNAM(50),BFLAB(512)
    COMMON/SCFOPT/SCFTYP
    COMMON/SCM/CORE(1)
    COMMON/WFNOPT/WFNTYP
 #N #BD.7 AMPAC VERSION#N

#ID.7.1 AMPAC sample input#N

0 A sample AMPAC input file that will create default  methy-
lamine (AM1 at Pople-Gordon idealized geometry) output simi-
lar to the #Iab initio#N output displayed in Section A.3  is
shown below:

AM1

CH3NH2...AM1//Pople-Gordon standard geometry
   C      0.000000  0    0.000000  0    0.000000  0    0   0
0
   N      1.470000  0    0.000000  0    0.000000  0    1   0
0
   H      1.090000  0  109.471230  0    0.000000  0    1   2
0
   H      1.090000  0  109.471230  0  120.000000  0    1   2



                       July 11, 1995





                          - 144 -


3
   H      1.090000  0  109.471230  0  240.000000  0    1   2
3
   H      1.010000  0  109.471230  0   60.000000  0    2   1
3
   H      1.010000  0  109.471230  0  300.000000  0    2   1
3

$NBO  $END

 #T

@seg


0 #NThe keylists of the NBO program should always appear  at
the  bottom  of  the AMPAC input file and should be ordered:
$NBO, $CORE, $CHOOSE, $DEL.  NBO job options are selected by
inserting  their  associated keywords (Section B.2) into the
$NBO keylist.

0 Due to the implicit orthogonality of the basis  functions,
the  following  NBO  keywords  are  not  applicable  to  the
wavefunctions computed by  AMPAC  (or  other  semi-empirical
packages):
 #T
       AOPNAO        AOPNLMO       NAONHO        SPNAO
       AONAO         DINAO         NAONLMO       SPNHO
       AOPNHO        DMNAO         NAOMO         SPNBO
       AOPNBO        FNAO          SAO           SPNLMO

#NIn addition, the NBO keywords that require access  to  the
AO  dipole  integrals  (DIPOLE,  DIAO,  DINAO, DINHO, DINBO,
DINLMO) are not applicable with AMPAC, since these integrals
are unavailable to the NBO program.




                          - 144 -
77777777777777777777777777777777777777770 The following is a modified AMPAC  input  file  that  will
generate,  in  addition  to the default NBO output, the NLMO
and the NBO energetic analyses of methylamine:

AM1

CH3NH2...AM1//Pople-Gordon standard geometry
   C      0.000000  0    0.000000  0    0.000000  0    0   0
0
   N      1.470000  0    0.000000  0    0.000000  0    1   0
0
   H      1.090000  0  109.471230  0    0.000000  0    1   2
0
   H      1.090000  0  109.471230  0  120.000000  0    1   2
3
   H      1.090000  0  109.471230  0  240.000000  0    1   2
3
   H      1.010000  0  109.471230  0   60.000000  0    2   1
3
   H      1.010000  0  109.471230  0  300.000000  0    2   1
3

$NBO  NLMO  $END $DEL  NOSTAR
      ZERO 2 ATOM BLOCKS  3 BY 4
                          1 3 4 5
                          2 6 7
                          4 BY 3
                          2 6 7
                          1 3 4 5 $END
 #T

@seg




                          - 144 -
7777777777777777777777777777777777777#ID.7.2 Sample NBO output for AMPAC wavefunctions#N

0 Since the AMPAC output  differs  in  significant  respects
from  the  #Iab initio#N examples presented in Sections A,B,
we present some excerpts from the NBO  output  and  a  brief
discussion  of  the NBO analysis of the AM1 wavefunction for
methylamine (Pople-Gordon idealized geometry).  The  numeri-
cal  values in these exerpts (summary tables) should be ade-
quate for checking purposes.

0 The summary of the Natural Population Analysis  (NPA)  for
methylamine is shown below:
Summary of Natural Population Analysis:

                                      Natural Population
              Natural                              ---------
--------------------------------------
   Atom #      Charge         Core       Valence     Rydberg
Total                                             ----------
-------------------------------------------------------------
     C   1    -0.13281       2.00000      4.13281    0.00000
6.13281
     N  2    -0.34739       2.00000      5.34739     0.00000
7.34739
     H  3     0.03346       0.00000      0.96654     0.00000
0.96654
     H  4     0.08488       0.00000      0.91512     0.00000
0.91512
     H  5     0.08488       0.00000      0.91512     0.00000
0.91512
     H  6     0.13849       0.00000      0.86151     0.00000
0.86151
     H  7     0.13849       0.00000      0.86151     0.00000
0.86151
=======================================================================
  *  Total  *   0.00000       4.00000    14.00000    0.00000
18.00000
 #T

@seg


0  #NNote  that  the  core  electrons  of  all  heavy  atoms
(neglected in the semi-empirical AMPAC procedure) are incor-
porated into the NPA, along the lines of  the  treatment  of
effective  core potentials (Section B.6.12).  Note also that
the numerical values of AM1 natural charges (and other quan-
tities) differ significantly from those presented in Section
A.3.2, reflecting a tendency toward  somewhat  reduced  bond
polarities in AM1 wavefunctions.







                       July 11, 1995





                          - 145 -


                          - 145 -
7The NBO summary table is shown below:
Natural Bond Orbitals (Summary):

                                                    Princi-
pal Delocalizations
          NBO                     Occupancy           Energy
(geminal,vicinal,remote)
===============================================================================
Molecular unit  1  (CH5N)
  1.  BD  (  1)  C  1-   N   2         1.99095     -20.60408
9(g),10(g),11(g),12(g),13(g)
  2.  BD  (  1)  C  1-   H   3         1.99184     -17.81012
8(g),10(g),11(g),9(g)
  3.  BD  (  1)  C  1-   H   4         1.98864     -17.75195
12(v),9(g),11(g),8(g)
  4.  BD  (  1)  C  1-   H   5         1.98864     -17.75195
13(v),9(g),10(g),8(g)
  5.  BD  (  1)  N  2-   H   6         1.98916     -19.74256
13(g),8(g),10(v)
  6.  BD  (  1)  N  2-   H   7         1.98916     -19.74256
12(g),8(g),11(v)
  7. LP ( 1) N 2            1.98489   -15.52775    9(v)
  8. BD*( 1) C 1- N 2       0.01048     4.75597
  9. BD*( 1) C 1- H 3       0.02306     4.29359
 10. BD*( 1) C 1- H 4       0.01070     4.57248
 11. BD*( 1) C 1- H 5       0.01070     4.57248
 12. BD*( 1) N 2- H 6       0.01090     5.27834
 13. BD*( 1) N 2- H 7       0.01090     5.27834
      -------------------------------
             Total Lewis   17.92328  ( 99.5738%)
       Valence non-Lewis    0.07672  (  0.4262%)
       Rydberg non-Lewis    0.00000  (  0.0000%)
      -------------------------------
           Total unit  1   18.00000  (100.0000%)
          Charge unit  1    0.00000
 #T

@seg


0 #NNote that in this case the orbital  energies  and  other
matrix elements of the Fock operator are printed in electron
volts, the energy units of the  AMPAC  package.   Note  also
that  the physical pattern of delocalization effects differs
significantly from that shown  in  Section  A.3.6,  the  AM1
results  portraying numerous strong #Igeminal#N interactions
that are not present in the  #Iab  initio#N  output.   Other
differences  between the AM1 and #Iab initio#N wavefunctions
will be evident throughout the NBO output.




                          - 145 -



                       July 11, 1995





                          - 146 -


0 Finally, we include the output  segment  showing  the  NBO
energetic analysis of methylamine:
NOSTAR: Delete all Rydberg/antibond  NBOs  Deletion  of  the
following orbitals from the NBO Fock matrix:
   8   9  10  11  12  13

Occupations of bond orbitals:

      Orbital                   No deletions   This deletion
Change                                            ----------
--------------------------------------------------------------------
  1.  BD  ( 1) C 1- N 2               1.99095        2.00000
0.00905
  2. BD ( 1) C 1- H 3                1.99184         2.00000
0.00816
  3. BD ( 1) C 1- H 4                1.98864         2.00000
0.01136
  4. BD ( 1) C 1- H 5                1.98864         2.00000
0.01136
  5. BD ( 1) N 2- H 6                1.98916         2.00000
0.01084
  6. BD ( 1) N 2- H 7                1.98916         2.00000
0.01084
  7. LP ( 1) N 2                     1.98489         2.00000
0.01511
  8. BD*( 1) C 1- N 2                0.01048         0.00000
-0.01048
  9. BD*( 1) C 1- H 3                0.02306         0.00000
-0.02306
 10. BD*( 1) C 1- H 4                0.01070         0.00000
-0.01070
 11. BD*( 1) C 1- H 5                0.01070         0.00000
-0.01070
 12. BD*( 1) N 2- H 6                0.01090         0.00000
-0.01090
 13. BD*( 1) N 2- H 7                0.01090         0.00000
-0.01090

NEXT STEP:  Evaluate the energy of the new density matrix
            that has been constructed from the deleted NBO
            Fock matrix by doing one SCF cycle.

---------
---------------------------------------------------------------------
  Energy of deletion :        22.024
    Total SCF energy :        -5.051
                         -------------------
       Energy    change    :            27.075     kcal/mol,
27.075                  kcal/mol                  ----------
--------------------------------------------------------------------
 #T

@seg




                       July 11, 1995





                          - 147 -


0 #NNote that the ``energy of  deletion''  (22.0  kcal/mol),
``total  SCF  energy'' (-5.1 kcal/mol) and ``energy change''
(27.1 kcal/mol) are all given in terms of  heats  of  forma-
tion,  the  standard  AM1 form of expressing molecular ener-
gies.




                          - 147 -
7777777777#ID.7.3 NBO program installation#N

0 The NBO interfacing (driver)  routines  provided  in  this
distribution  were written for AMPAC, version 1.00.  Section
D.7.4 lists the AMPAC dependent elements of the  NBO  driver
routines  that  may  need slight modification for other ver-
sions of the AMPAC program.

0 Only one command line is added to the AMPAC source code to
run  the  NBO analysis.  A command ``CALL RUNNBO'' should be
inserted in the AMPAC properties package (SR WRITE in module
WRITE), as shown below:

      SUBROUTINE WRITE(TIME0,FUNCT)

      .
      .
      .

         X=MECI(EIGS,C,CBETA,EIGB, NORBS,NMOS,NCIS, .TRUE.)
      ENDIF C C     <<< BEGINNING OF NBO INSERT >>> C
      CALL RUNNBO C C     <<< END OF NBO INSERT >>> C
      IF (INDEX(KEYWRD,'MULLIK') +INDEX(KEYWRD,'GRAPH') .NE.
0) THEN
         IF (INDEX(KEYWRD,'MULLIK') .NE. 0) THEN

      .
      .
      .
 #T

@seg


0 #NThe NBO analysis is performed  each  time  SR  WRITE  is
called.   For  example,  the  NBO  analysis  of the computed
wavefunction will be performed for every single point calcu-
lation  and  at  the end of geometry optimizations.  The NBO
output will appear immediately after the Mulliken Population
Analysis in the AMPAC output file.

0 The NBO program installation should continue as  discussed



                          - 147 -
7777777777777777777777777777777777777777777777in Section A.2.
#ID.7.4 NBO communication with AMPAC#N

0 The NBO driver routines (RUNNBO,  FEAOIN,  DELSCF)  access
the following AMPAC routines and COMMON blocks:

#_AMPAC routines:#T#/

    SR GMETRY(GEO,COORD)
    SR HCORE(COORD,H,W,WJ,WK,ENUCLR)
    SR FOCK2(F,PTOT,P,W,WJ,WK,NUMAT,NFIRST,NMIDLE,NLAST)
    SR FOCK1(F,PTOT,PA,PB)
    FN HELECT(N,P,H,F)

#_#NAMPAC COMMON blocks:#T#/

    INCLUDE 'SIZES'
    COMMON /ATHEAT/ ATHEAT
    COMMON /DENSTY/ P(MPACK),PA(MPACK),PB(MPACK)
    COMMON /ENUCLR/ ENUCLR
    COMMON /FOKMAT/ F(MPACK),FB(MPACK)
    COMMON                                          /GEOKST/
NATOM,LABELS(NUMATM),NA(NUMATM),NB(NUMATM),
   +                NC(NUMATM)
    COMMON /GEOM  / GEO(3,NUMATM)
    COMMON /HMATRX/ H(MPACK)
    COMMON /KEYWRD/ KEYWRD
    COMMON                                          /MOLKST/
NUMAT,NAT(NUMATM),NFIRST(NUMATM),NMIDLE(NUMATM),
   +
NLAST(NUMATM),NORBS,NELECS,NALPHA,NBETA,NCLOSE,
   +                NOPEN,NDUMY,FRACT
    COMMON /NATORB/ NATORB(107)
    COMMON /TITLES/ COMENT(10),TITLE(10)
    COMMON                                          /VECTOR/
C(MORB2),EIGS(MAXORB),CBETA(MORB2),EIGB(MAXORB)
    COMMON /WMATRX/ WJ(N2ELEC),WK(N2ELEC)
 #N #N



#HINDEX#N


 Acceptor orbital,A21
 ACS Software,A11
 AMPAC version,A2,A7,A8,B66,C17
 Angular symmetry labels,A5,#IB68#N,C7
 Antiperiplanar interaction,A19,A23,B50
 Archive file (FILE47),A5,
        #IB62-71#N,C8,C14,C31,C36
 Arrays
      IBXM,C9,C22,C23
      JPRINT,C6



                       July 11, 1995





                          - 148 -


NBOOPT,C16,#IC17#N,C18,
            C26,C30,C36,C39
 Atom-centered basis functions,A1
 Atomic charge,A14
 Atomic orbitals,A1,A5,A6,B67-68
      Contracted gaussian,A6,B69-70
      Pure (PAO),#IB11#N,B67-68,C19,C30
      Slater-type,A6
      #Isee#N Atomic shell
      #Isee#N Core orbitals
      #Isee#N Pre-orthogonal orbitals
 Atomic shell
      Core,A7,A8,A13,A14,A16,C24
      Rydberg,A2,A8,A13,A14,A16,C25
      Valence,A8,A13,A14,A16
 Atomic units,A13,B65,C4,C13
 Attaching NBO to ESS program,
        A10-11,C36,C38-39
 AUHF method
      #Isee#N Wavefunction type
 Azimuthal                     angle                     (hi
),A20,C33

 Basis set
      #Isee#N Atomic orbitals
 Benzene (C#d6#uH#d6#u),B3,B32-36
 Bond bending,A8,A20
      #Isee#N Hybrid direction
 BONDO program,A7
 Bond order,B29-31
      Matrix,B11,B65,C19
 Boys LMOs,B3
 Brunck, T. K.,A7

 Canonical MOs,B6,B27-28,B71,C20
 Carpenter, J. E.,A7
 Chemical fragment,#IB16#N,B19
 $CHOOSE list
      #Isee#N Keylists
 Comments (!),B1,B63,C29
 Comment statements,C1
 COMMON blocks
      /NBAO/,C7
      /NBATOM/,C7
      /NBBAS/,C9,C22,C31,C30
      /NBCRD1/,C11,C29
      /NBCRD2/,C12,C29
      /NBDAF/,C12,C27,C28
      /NBDXYZ/,C11
      /NBFLAG/,C5
      /NBGEN/,C13,C30
      /NBINFO/,C4
      /NBIO/,C8,C18
      /NBLBL/,C10,C32



                       July 11, 1995





                          - 149 -


/NBMOL/,C10
      /NBNAO/,C10
      /NBONAV/,C12
      /NBOPT/,C6-7,C18,C30
      /NBTHR/,C9,C18
      /NBTOPO/,C11,C22
 Contour plotting program,A8,B9,B69
 Contracted gaussian orbitals
      #Isee#N Atomic orbitals
 Copper dimer (Cu#d2#u),B56-61
 $CORE list
      #Isee#N Keylists
 Core orbitals,A6,A7,A8,A16,
        B12-13,B56-61,B66,C24,C30,C33
 Core polarization,A8,B12
 Core table,B12,C33

 DAF
      #Isee#N Direct access file
 Datalists,B63-64
      $BASIS,#IB67-68#N,B71,C31,C37
      $CONTRACT,#IB69-70#N,C31,C37
      $COORD,B63,B65,#IB66#N,C31,C37
      $DENSITY,B71
      $DIPOLE,B65,B71,C37
      $FOCK,B65,B71,C37
      $LCAOMO,B71,C37
      Matrix,B71
      $OVERLAP,B65,B71,C37
 #Id#N-orbitals,B53,B56,B61
 Default output,A12,B10
 Deletion types,B17-19
 $DEL (deletions) list
      #Isee#N Keylists
 Delocalization,A1,A2,A21,B3,B32,B51
 Delocalization tail,A22,B23
 Density matrix,A1,A5,A6,B6-7,C13
      #Isee#N Bond-order matrix
      #Isee#N Spin density matrices
 Depletion of density matrix,C24
 Diborane (B#d2#uH#d6#u),B40-43
 Dictionary file,A4
 Different Lewis structures for
   different spin
      #Isee#N Open-shell calculation
 Dimension specification,C4
 Dipole moment,A5,A6,A8,B5,B6-7,
        #IB24-25#N,B65,B71,C11,C15,C24
 Direct access file (FILE48),A3,A4,A5,
        B9,B65,C12,#IC14-15#N,C16,C27,
        C28,C36-39
 Directed NBO search
      #Isee#N Keylists, $CHOOSE
 Directional analysis



                       July 11, 1995





                          - 150 -


#Isee#N Hybrid direction
 Distribution tape,A10
 Donor orbital,A21,A22
 Double-bond, no-bond resonance,B44-47
 Driver routines,A3
      #Isee#N Subroutines RUNNBO, etc.

 Edmiston-Ruedenberg LMOs,B3
 Effective core potential (ECP),
        A8,#IB56-61#N,B66
 Electronic structure system (ESS),A3
      Common blocks,A4
      Connection to NBO program,A3,A4,A7,
         A10-11,B56,B62,C36,C38-39
      Input file,A5,A11,A12
      Output file,A5,A12
      Scratch files,A4
      #Isee#N AMPAC, GAUSSIAN-8X, #Ietc.#N
 ENABLE program,A10,C36
 Energetic analysis,A3,A5,#IB16-19#N,
        C2,C26,C38,C39
      #Isee#N Perturbation theory...
 Excited state,A6,A8,A15,B56,C23

 #If#N-orbitals
      #Isee#N Angular symmetry labels
      #Isee#N Keyword CUBICF
 Fenske-Hall method
      #Isee#N MEDVL
 Fetch/Save routines,C15,C27
 FILE48
      #Isee#N Direct access file
 FILE47
      #Isee#N Archive file
 Flow chart,A4,C3,C16
 Fock matrix,A2,A5,A6,A8,A14,A21,
        B6,B16-20,B26,B48-51,B65,B71,
        C2,C23,C26,C39
 Fortran 77,A6,A10
 Foster, J.P.,C22
 Free format,B1,C29
 Freezing a transformation,B8
 Functions
      EQUAL,C29
      IHTYP,C34
      IOINQR,C32
      IWPRJ,C24
      NAMEAT,C34
      VECLEN,C35

 GAMESS version,A1,A2,A7,A10,A12,C17
 Gaussian elimination,C35
 GAUSSIAN-8X version,A2,A7,
        A10,B56,C17



                       July 11, 1995





                          - 151 -


Geminal interaction,A22,B18,C33
 Generalized eigenvalue problem,C20
 GENNBO input file
      #Isee#N Archive file
 GENNBO stand-alone program
        A10,B9,B62-71,C13,C36,C37,C38
 Geometry,B66
 Glendening, E. D.,A7
 Groups of routines
      I   (NAO/NBO/NLMO),C2,C16-25
      II  (energy analysis),C2,C26
      III (direct access file),C2,C27-28
      IV  (free format input),C2,C29
      V   (other I/O),C2,C30-32
      VI  (general utility),C2,C33-35
      VII (system-dependent),C2,C36
 GUGA formalism,A1
 GVB method
      #Isee#N Wavefunction type

 Hay-Wadt ECP,B56
 HONDO version,A2,A10,C17,C27
 Hybrid composition,A19,B23
 Hybrid direction,A8,#IA20#N,B4,C23
 Hydrogen fluoride (HF),B37-39

 I/O routines
      #Isee#N Groups of routines
 INP routines,C30,C39
 Input file,A5,B62,C14
 Installation procedure,A10-11
 Ionic hybrids,B37-39

 Job control keywords,B2,B3
 Job initialization routines,C16,C18
 Job threshold keywords,B2,B4-5

 Kekulcute e structure,B36
 Keylist,A5,A11,A12,#IB1#N
 Keylists
      $CHOOSE,B1,B2,B12,#IB14-15#N,#IB44-47#N,
           B62,B63,B65,C6,C22,C30
      $CORE,B1,B2,#IB12-B13#N,
           B62,B63,B65,C3,C6-7,C30
      $DEL,B1,B2,B12,#IB16-20#N,
           #IB48-51#N,B62,C17,C26,C30
      $GENNBO,#IB65#N,B66,C30
      $NBO,B1,#IB2-11#N,B21-43,B62,B63,
           B65,B69,C6,C17,C18,C22,C30
 Keyword names (matrix output),B6-7
 Keyword parameters (matrix output),B7-8
 Keywords
      AOINFO,B2,#IB9#N,B69,B71,C6,C31
      AOMO,B2,B6,B71,C6



                       July 11, 1995





                          - 152 -


AONAO,B2,B6,C6,C30-31
      AONBO,B2,B6,C6,C31
      AONHO,B2,B6,C6
      AONLMO,B2,B3,B6,C6,C31
      AOPNAO,B2,B6,B71,C6
      AOPNBO,B2,B6,B71,C6
      AOPNHO,B2,B6,B71,C6
      AOPNLMO,B2,B6,B71,C6
      ARCHIVE,B2,#IB9#N,#IB62-71#N,C6,C31
      BEND,A8,#IA20#N,B2,#IB4#N,B5,B10,C6,C23
      BNDIDX,B2,#IB9#N,B10,B21,
         #IB29-B31#N,C6
      BOAO,B11,C6
      BODM,#IB65#N,C6,C13
      BOHR,#IB65#N,B66,,C13
      CUBICF,#IB65#N,B68,C6
      DESTAR,B18
      DETAIL,B2,#IB9#N,C6
      DIAO,B2,B7,B71,C6
      DINAO,B2,B7,B71,C6
      DINBO,B2,B7,B71,C6
      DINHO,B2,B7,B71,C6
      DINLMO,B2,B6,B7,B71,C6
      DIPOLE,A8,B2,B3,#IB5#N,B10,B21,
         #IB24-25#N,B71,C6,C17,C24
      DMAO,B2,B7,C6
      DMNAO,B2,B7,C6
      DMNBO,B2,B7,C6
      DMNHO,B2,B7,C6
      DMNLMO,B2,B7,C6
      E2PERT,#IA21#N,B2,#IB4#N,B5,B10,B71,C6
      EV,B65
      FAO,B2,B7,B71,C6
      FNAO,B2,B7,B71,C6
      FNBO,B2,B6-8,B7,B71,C6
      FNHO,B2,B7,#IB26#N,B71,C6
      FNLMO,B2,B7,B71,C6
      LFNPR,B2,#IB9#N,C8
      Matrix output,B6-8,B26-28
      MULAT,B11,C6
      MULORB,B11
      NAOMO,B2,B6-8,B71,C6
      NAONBO,B6-8,C6
      NAONHO,B6-8,C6
      NAONLMO,B6-8,C6
      NATOMS,B65
      NBAS,B65
      NBODAF,B2,B9
      NBO,#IA16-19#N,B2,#IB3#N,B10,C6
      NBOMO,B2,B6-8,#IB27-28#N,B71,C6
      NBONLMO,B2,B6-8,C6
      NBOSUM,#IA22-23#N,B2,#IB3#N,B10,C6,C23
      NHOMO,B2,B6-8,B71,C6
      NHONBO,B2,B6-8,C6



                       July 11, 1995





                          - 153 -


NHONLMO,B2,B6-8,C6
      NLMO,B2,#IB3#N,B5,B10,#IB22-23#N,C6
      NLMOMO,B2,B6-8,B71,C6
      NOBOND,B2,#IB3#N,B21,#IB37-39#N,C6
      NOGEM,B18
      NOSTAR,B18,#IB48-49#N
      NOVIC,B18
      NPA,#IA13-15#N,B2,#IB3#N,B10,C6,C20
      OPEN,B65
      ORTHO,B65
      PAOPNAO,B11,C6
      PLOT,A8,B2,#IB9#N,B69,B71,C6
      PRINT,B2,B5,#IB10#N,B71,C18,C6
      PRJTHR,B11
      RESONANCE,A16,B2,#IB3#N,B21,
         #IB32-36#N,C6,C17,C25
      REUSE,#IB65#N,B66,B67,C13
      RPNAO,B11,C6
      SAO,B2,B7,B71,C6
      SKIPBO,B2,#IB3#N,B10,C6
      SPNAO,B2,B6-8,B7,B71,C6
      SPNBO,B2,B7,B71,C6
      SPNHO,B2,B7,B71,C6
      SPNLMO,B2,B3,B7,B71,C6
      3CBOND,B2,#IB3#N,B14,B21,#IB40-43#N,C6
      THRESH,B11
      UPPER,B65,B71,C13
      ZERO,B19,#IB49-51#N
 Kinks
      #Isee#N Hybrid direction, Bond bending

 Labelled COMMON blocks,A3,A6,C4-13
      #Isee#N COMMON blocks
 Lewis orbitals
      #Isee#N Natural bond orbitals
 Linear equations package,C35
 Linear independence,A1,C22,C24
 Logical file number (LFN),C8,C38,C39
 L8mlaut owdin, P.-O.,A1
 L8mlaut owdin orthogonalization,C21

 Matrix multiplication,C34
 Matrix output keywords,
        B2,#IB6-8#N,B9,#IB26-28#N,C7
 Mayer-Mulliken bond-order,C19
 MCSCF method
      #Isee#N Wavefunction type
 MEDVL version,A10
 Memory allocation,
        A6,A12,C16,C18,C19,C22
 Methylamine (CH#d3#uNH#d2#u),
        A12-23,B21-31,B44-51,B63-71
 Methyl radical (CH#d3#u),B52-55
 Molecular units,#IB16#N,B18,B19,C10,C23



                       July 11, 1995





                          - 154 -


M0t oller-Plesset method
      #Isee#N Wavefunction type
 MOPAC version,A10
 Mulliken population analysis,
         A10,B11,C19,C38
 Multiple bonds,A19,B14,B44-47,B56-61

 Naaman, R.,A7
 NAO formation routines,C16,C19-21
 Natural atomic orbital (NAO)
      Formation,A1,A7,C16,C19-21
      Labels,A13-14,C10
      Listing,A13,C10
      Summary table,A7
      #Isee#N Natural population analysis
 Natural bond orbital (NBO)
      Analysis,A1-2,A16-19
      Formalism,A1-A2,A7
      Labels,A8,A19,B27-28,B43,C9,C10,C32
      Lewis,A2,A16,A19,A21,A23,B48-51,B17
      Listing,#IA17-19#N,B2
      Non-Lewis,A2,A16,A19,
         A21,A23,B17,B18,B48-51
      Summary table,#IA22-23#N,C23
      3-center,A16,#IB40-43#N
      #Isee#N Perturbation theory...
      #Isee#N NBO/NLMO formation routines
 Natural electron configuration (NEC),
        A7,#IA15#N,C20
 Natural hybrid orbital (NHO)
      Directional analysis,A20
      Formation,A1-2
      Labels,B26,C10
      Listing,A-19
      #Isee#N Natural bond orbitals
      #Isee#N Hybrid direction
 Natural Lewis structure,A1-2,A16,
        A19,B3,B18,B48,B49
      Energy,B18,B48
 Natural localized molecular orbital (NLMO)
      Formation,A7,B3,C25
      Listing,B3,#IB22-23#N
 Natural minimal basis (NMB) set,A2,A14
 Natural population analysis (NPA),
         A3,A6,A7,#IA13-14#N,B3,
         B10,B21,B56-57,C20
 Natural Rydberg basis (NRB) set,A2,A18
 NBO direct access file
      #Isee#N Direct access file
 $NBO keylist
      #Isee#N Keylists
 NBO energetic analysis
      #Isee#N Energetic analysis
      #Isee#N Perturbation theory...



                       July 11, 1995





                          - 155 -


NBO.MAN file,A10,A11
 NBO/NLMO formation routines,
        C16,C22-25
 NBO program,Section C
      I/O,A5,A12,C27-32
      Installation,A10-11
      Organization,A3-4,C2-4
      Restrictions,A6
      #Isee#N Electronic structure system
 NBO.SRC file,A10,C1,C2
 NBO summary table,#IA22-23#N,C23
 NLMO/NPA bond order,B30-31
 Non-Lewis orbitals
      #Isee#N Natural Bond Orbital

 Open-shell calculation,
        A1,A5,B14,B25,#IB52-55#N,B65,C5
      #Isee#N Wavefunction type
 Orbital contour plotting program,
        A8,B9,B69
 Orthogonalization,C20
      L8mlaut owdin (symmetric),C24
      Occupancy-weighted (OWSO),C20,C21
      Schmidt,C20
 Output control keywords,B2,#IB9-10#N
 Output file,A8,A12,C1
 Overlap matrix,A5,A6,A8,B6,B71,C38
      singularities,C25
 Overlap-weighted NAO bond order,B30

 Perturbation theory energy analysis,
        A8,#IA21#N,B3,B4,C23,C39
 Phi,A20,C33
 PNAO, PNBO, PNHO, PNLMO
      #Isee#N Pre-orthogonal orbitals
 Polar angle (heta ),A20,C33
 Polarization coefficients,A2,A19,C25
 Pople-Gordon geometry,A12,A20,B21,B32
 Population analysis
      #Isee#N Mulliken population analysis
      #Isee#N Natural population analysis
 Population inversion,A14,B57
 Pre-orthogonal orbitals,
         A1-2,A6,A8,B6,B65,B71
 Print parameters,B2,#IB7-8#N,
         B11,B27-28,C7,C10
 Program groups,C2
      #Isee#N Groups of routines
 Program limits
      Atoms,A6,C4
      Basis functions,A6,C4
 Program precedence,C2,C3
 Pseudopotential
      #Isee#N Effective core potential



                       July 11, 1995





                          - 156 -


Pure AOs,B11
      #Isee#N Atomic orbital

 QCPE,A7,A8

 Read (R) parameter
      #Isee#N Print parameters
 Read-write file,A4
 Reed, A. E.,A7,B11,B31,C19
 References,A7
 Remote interaction,A22,C33
 Resonance structures,A9,B14-15,B32-33,
        B38,B39,B44-47,C11,C25
 Rewind input file,C39
 RHF method
      #Isee#N Wavefunction type
 Rives, A. B.,A7
 ROHF method
      #Isee#N Wavefunction type

 Schleyer, P. v.R.,B31
 2nd-order perturbation theory analysis
      #Isee#N Perturbation theory energy...
 Semi-documented keywords,B2,#IB11#N
 Similarity transformation,C19,C26,C34
 Slater-type orbitals
      #Isee#N AO basis functions
 Spin
      #Isee#N Open-shell calculations
 Spin-annihilated UHF (AUHF) method
      #Isee#N Wavefunction type
 Spin density matrices,A1,B52-55,C5
 Storage
      #Isee#N Memory allocation
 Subroutines,C2,C3
      ANGLES,C33
      ANLYZE,C23
      AOUT,C31
      APRINT,C31,C32
      AREAD,C31
      ATDIAG,C20
      AUGMNT,C25
      AWRITE,C31
      BDFIND,C33
      BLDSTR,C23
      CHEM,C33
      CHOOSE,C22,C23,C24
      CHSDRV,C22
      CHSINP,C30
      CONSOL,C33
      CONVIN,C33
      CONVRT,C33
      COPY,C33
      CORE,C24



                       July 11, 1995





                          - 157 -


CORINP,C30
      CORTBL,C33
      CYCLES,C22,C25
      DEBYTE,C33
      DELETE,C26
      DELINP,C30
      DELSCF,A3,A4,A5,C2,#IC36#N,C38,C39
      DEPLET,C24
      DFGORB,C19,C30
      DIPANL,A6,C22,C24
      DIPELE,C24
      DIPNUC,C24
      DMNAO,C19
      DMSIM,C19
      FACTOR,C35
      FEAOIN,A3,A4,A5,C2,C6,
         C14,#IC36#N,C38,C39
      FEAOMO,C27
      FEAOM,C27
      FEBAS,C27
      FECOOR,C27
      FEDNAO,C27
      FEDRAW,C27
      FEDXYZ,C27
      FEE0,C27
      FEFAO,C27
      FEFNBO,C27
      FEINFO,C27
      FENBO,C27
 Subroutines (#Icontinued#N)
      FENEWD,C27
      FENLMO,C27
      FEPNAO,C27
      FEPPAO,C27
      FESNAO,C27
      FESRAW,C27
      FETITL,C27
      FETLMO,C27
      FETNAB,C27
      FETNAO,C27
      FETNBO,C27
      FETNHO,C27
      FNBOAN,C23
      FNDFLD,C29
      FNDMOL,C23
      FNDSOL,C35
      FORMT,C25
      FRMHYB,C23
      FRMPRJ,C25
      FRMTMO,C20
      GENINP,C30
      GETDEL,C23
      HALT,C33
      HFLD,C29



                       July 11, 1995





                          - 158 -


HTYPE,C23
      HYBCMP,C23
      HYBDIR,C23
      IDIGIT,C33
      IFLD,C29
      INTERP,C32
      JACOBI,C25,C34
      JOBOPT,C18,C29
      LBLAO,C32
      LBLNAO,C32
      LBLNBO,C32
      LBLNHO,C32
      LIMTRN,C34
      LINEQ,C33,C35
      LMOANL,C24
      LOADAV,C20
      LOAD,C24
      MATML2,C34
      MATMLT,C34
      MULANA,C19
      NAOANL,C21
      NAODRV,C2,C19
      NAOSIM,C19
      NAO,C19
      NATHYB,C22,C23,C24
      NBCLOS,C16,C28
      NBINQR,C28
      NBOCLA,C23
      NBODEL,C26
      NBODIM,C18
      NBODRV,C2,C19,C22
      NBOEAN,A3,A4,A6,C3,C26,C36,C39
      NBOINP,C30
      NBOPEN,C16,C27
      NBOSET,C18,C39
      NBO,A3,A4,C2,C16,C36
      NBOSUM,C23
      NBREAD,C28
      NBWRIT,C28
      NEWDM,C26
      NEWRYD,C20
      NEWWTS,C20
      NLMO,C22,C24
      NORMLZ,C34
      ORDER,C34
      ORTHYB,C24
      OUTPUT,C32
      PACK,C34
      PRJEXP,C24
      RANK,C34
      RDCARD,C29
      RDCORE,C30
      RDPPNA,C30
      RDTNAB,C31



                       July 11, 1995





                          - 159 -


RDTNAO,C31
      REDBLK,C21
      REDIAG,C21
      REPOL,C25
      RFLD,C29
      RNKEIG,C26
      RUNNBO,A3,A4,#IC36#N,C38,C39
      RYDIAG,C20
      RYDSEL,C21
      SETBAS,C20
      SHMDT,C20
      SIMLTR,C26
      SIMTRM,C19
      SIMTRN,C34
      SIMTRS,C34
      SRTNBO,C22
      STASH,C24
      STRTIN,C29
      SUBST,C35
      SVDNAO,C27
      SVE0,C27
      SVFNBO,C27
      SVNBO,C27
      SVNEWD,C27
      SVNLMO,C27
      SVPNAO,C27
      SVPPAO,C27
      SVSNAO,C27
      SVTLMO,C27
 Subroutines (#Icontinued#N)
      SVTNAB,C27
      SVTNAO,C27
      SVTNHO,C27
      SYMORT,C25
      SYMUNI,C25
      TRANSP,C34
      UNPACK,C35
      VALTBL,C35
      WRARC,C31
      WRBAS,C31
      WRMLMO,C31
      WRPPNA,C30
      WRTNAB,C31
      WRTNAO,C30,C31
      WRTNBO,C312
      XCITED,C23
 Symmetric orthogonalization,C24,C25
 Symmetry,B16
 System-dependent driver routines,C36

 TechSet,A11,A20
 Theta,A20,C33
 3-center bonds
      #Isee#N Natural bond orbitals



                       July 11, 1995





                          - 160 -


Thresholds,C9
      ALLOW2,C20
      ALLOW,C20
      ANG,B4
      ATHR,C23
      DANGER,C20,C25
      DIAGTH,C20,C25
      DIFFER,C24,C34,C34
      DONE,C34
      DVAL,B5,B25
      EPS,C24,C34
      ETHR1,C23
      ETHR2,C23
      ETHR,C23
      EVAL,B4
      OCC,B4
      PCT,B4
      PRJINC,C22
      PRJTHR,B11,C22
      PTHR,C23
      TEST2,C20
      TEST,C20
      THRESH,C22
      THR1,C23
      THR2,C23
      THRESH,B11,C25
      TOOSML,C24
      WORTH,C20
      WTTHR,C20,C21
 2e-stabilization,A21

 UHF method
      #Isee#N Wavefunction type
 Upper triangular matrix,
        B65,B71,C13,C33,C34

 Vager, Z.,A7
 Valency index
      #Isee#N Bond order
 Versions, previous,#IA7#N,A9,B13
 Vicinal interaction,A22-23,B18,
        B23,B25,B51,C33

 Warnings,B16,B17,B36,B55
 Wavefunction type
      AUHF,C5,C17
      CI,A6,C5,C17
      Complex,A6,C5
      Correlated,B25
      GVB,A6
      MCSCF,A1,A6,C5
      M0t oller-Plesset,A6,C17
      RHF,A6,A12,B16,B56,C2
      ROHF,A6,C5



                       July 11, 1995





                          - 161 -


SCF,A6,B16,B25,C17
      Semi-empirical,A7,A8,B66
      UHF,A6,B16,B20,B52-55,C2,C5
 Weinhold, F.,A7,B11,C19,C22
 Weinstock, R. B.,A7,B11,C19
 Wiberg bond index,A16,B9,B29,C20,C22
 Write (W) parameter
      #Isee#N Print parameters

















































                       July 11, 1995


Modified: Tue Jul 11 16:00:00 1995 GMT
Page accessed 1718 times since Sat Apr 17 17:43:17 1999 GMT