Subject: AIM in g98 problems - NO GOOD SOLUTION --- SUMMARY

From: Grzegorz Bakalarski <[email-masked]>
Date: Fri, 23 Nov 2001 12:38:18 +0100

Dear CCLer

Few days ago I've asked about AIM in Gaussian 98, which failed for
calculations performed by my collegue (she wants to get AIM derived
bond orders).
Unfortunately noone gave a solution for this particular problem.
Few people advised to use AIM2000 package from Prof. Bader's group,
but this program does not calculate explicitly bond orders.
One pointed out that it is possible to estimate bond order 
> from electronic density at critical point (for bond) usuing
formulae given by Prof. Bader (but probably my collegue
would have to fit again parameters in this formulae for DFT 
and used basis set).
One also suggested to use NBO instead of AIM.
Many thanks for all who responded.

Best regards,

gb

P.S. I also take a loot at Prof. Bader's group's page:
http://www.chemistry.mcmaster.ca/faculty/bader/aim/

                      *******************
***********************HERE IS SUMMARY: *******************
                      *******************

-----------------My query------------------------------
A collegue of mine wants to calculate bond orders in
guanine molecule and its modifications. She uses g98
and AIM(BO,tight) keyword. She tried different methods and different
bases but with no success (she tried b3lyp and HF with
bases: STO-3G, 3-21G, 6-31G, 6-31(d), 6-31+G(d,p).
The only result is that she got every  possible error
message (i.e. that some critical points are missing,
Newton minimizer fails etc) She also tried to use
some IOps (e.g IOp(6/36= ..) IOp(6/38=...) IOp(6/39=...)
IOp(6/55=...) but with no success.
Is there any tested set IOp's she should try? Or any other
solution?
Any help is welcome!

gb

----------- From: y tantirungrotechai <[email-masked]> --------
Hi,
The best solution is to use density(current) and
output(wfn) and punch out the .wfn file. Then use it
with Prof. Bader's aimpac or aim2000 developed by his
former coworker. Both are free and can download from
the net.
 
What you need to add in, for example
*******begin**********
#p density(current) output(wfn)

molecule specfication

nameofoutput.wfn

**********end ***********

Hope this help.
Yuthana Tantirungrotechai

--------------- From: Matthias Lein <[email-masked]> ------
Maybe you can use the original aimpac by the Bader group. You just have
to create a .wfn file with e.g. g98 and let the aimpac suite of programs
do the analysis.

Cheers,
Matthias.

------------From: y tantirungrotechai <[email-masked]> ---------------------
Hi,
Check Bader's book or
http://www.ch.ic.ac.uk/ectoc/echet98/pub/048/node8.htm
There is an expression relating the bond order and the
electron density at the bond critical point. So
basically get the density at the bond critical point
> from aimpac or aim2000 and use the formula as
indicated.

Best regards,
Yuthana Tantirungrotechai

------------ From: Peeter Burk <[email-masked]> ---------------------
A much better (robust) implementation of AIM analysis is in the original
program suite from prof. Bader's group in McMasters University
(Canada). The program was (at least some time ago) freely downloadable
> from their web site (which I unfortunately do not have at a moment).
 
Hope that helps
                Peeter

-------------From: Steve Williams <[email-masked]> ----------------
>Do you think that in AIM2000 program there is easy way
>to calculate BOND ORDERS????? I've downloaded the
>program and cannot find how ... Should I integrate
>over some basins ???

Unfortunately, the answer is no.  As far as I know, the only population
based AIM method for getting bond orders is in gaussian.  Anything else you
might want to do with aim is easier with aim2000, but it does not do bond
orders.  However, you can calibrate the critical density to give bond
orders, as described in Bader's book.  This involves choosing a scale
factor such that the exponential function in Bader's book gives 1, 2, or 3
> from the critical density for ethane, ethene, and ethyne for instance.  You
can then get other c-c bond orders from the critical densities in your
molecule.
Steve

---------------- From: Eric Glendening <[email-masked]> --------
Your colleague might consider using the NBO analysis.  The NBO program
is straightforward to use and very efficient.  It is distributed
(version 3.1) with Gaussian 98.  Several measures of bond order
are evaluated.  For example, following input
 
-------------------------------
#b3lyp/6-31g* pop=nboread
 
Formamide...b3lyp/6-31g*

0  1
C     0.000000    0.420333    0.000000
O     1.201750    0.236462    0.000000
N    -0.940819   -0.565065    0.000000
H    -0.457873    1.430460    0.000000
H    -0.642312   -1.531146    0.000000
H    -1.928080   -0.357560    0.000000

$nbo bndidx $end

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

prints the Wiberg bond indices.

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

 Wiberg bond index matrix in the NAO basis:

     Atom    1       2       3       4       5       6
     ---- ------  ------  ------  ------  ------  ------
   1.  C  0.0000  1.7226  1.2109  0.8934  0.0065  0.0028
   2.  O  1.7226  0.0000  0.1920  0.0710  0.0064  0.0188
   3.  N  1.2109  0.1920  0.0000  0.0065  0.8013  0.8118
   4.  H  0.8934  0.0710  0.0065  0.0000  0.0177  0.0000
   5.  H  0.0065  0.0064  0.8013  0.0177  0.0000  0.0001
   6.  H  0.0028  0.0188  0.8118  0.0000  0.0001  0.0000

 Wiberg bond index, Totals by atom:

     Atom    1
     ---- ------
   1.  C  3.8361
   2.  O  2.0107
   3.  N  3.0224
   4.  H  0.9885
   5.  H  0.8319
   6.  H  0.8335

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

More information about NBO is at http://www.chem.wisc.edu/~nbo5

Eric Glendening

---

From: "C.F. Matta" <[email-masked]>
Date: Fri, 23 Nov 2001 13:39:12 -0500 (EST)

Dear Dr. Bakalarski

I am sorry to answer you with some delay.

I understand you would like to compute "bond orders (B.O.)" using the
equation which relates it empirically to the electron density at the bond
critical point Rho(b):

	B.O.  =  exp { c [ Rho(b)  - c' ]  }.

I suggest that instead of this empirical relationship, you may perhaps
whish to consider a "real physical measure" of the degree of electron
sharing between two atoms (whether bonded or not).

I refer to the AIM delocvalization indices (delta). This gives you
directly the number of pairs shared between any two atoms in a molecule,
whether they are linked by a bond path or not (Sure enough the
delocalization index is much higher when there is a bond path). The
delocalization index is defined in terms of the product of the overlap
integrals integrated over atomic basins:

	Delta(atomA, AtomB) = 4 SUM(i)SUM(j) Sij(atomA) Sij(atomB)

where the factor 4 arises from 2(alpha and beta electrons) x 2
(contribution AB + contribution BA, which are equal).

To give you a few numerical examples:  Delta (N,N)=3.005 pairs in N2
molecule, Delta (H,H) = 1.000 in H2, Delta (C,C) =1.00 and Delta (C,H) =
0.99 in ethane, Delta (C,C) =1.85 in ethylene, and Delta (C,C) = 1.39 in
benzene.

We have used this index extensively in the recent literature.

The way to calculate it:

(1) Generagte the wavefunction.
(2) Perform the atomic integrations using AIMPAC (taking care to turn on
    the "overlap matrix" option ON during the atomic integrations.
    AIMPAC is available free of charge at:
	http://www.chemistry.mcmaster.ca/aimpac/
(3) Use the program AIMDELOC to calculate the localization and
    deloxcalization indices matrix. (available either directly from
    myself) or from the QCPE web site:
	http://qcpe.chem.indiana.edu/

REFERENCES:
===========
(1) Definition of the delocalization and localization indeces:

Fradera, X., Austen, M.A. & Bader, R.F.W. (1999) "The Lewis model and
beyond".  J. Phys. Chem. A, 103, 304-314.

Bader, R.F.W., Streitwieser, A., Neuhaus, A., Laidig, K.E. & Speers, P.
(1996) "Electron delocalization and the Fermi hole."  J. Am. Chem. Soc.,
118, 4959-4965.

(2) Program to calculate the delocalization and localization indices:

Matta, C. F.  (2001) "AIMDELOC01 (QCPE0802): Program to calculate AIM
localization and delocalization indeces". Quantum Chemistry Program Exchange,
Indiana University. (http://qcpe.chem.indiana.edu/  )

(3) Recent example of application of the delocalization indeces in
organometallic chemistry:

Bader, R.F.W. & Matta, C.F. (2001) Bonding to titanium.  Inorg. Chem.,
40, 5603-5611.

Best wishes.

  Cherif
___________________________________________________________________________

  Cherif F. Matta		    	  tel. (905) 525-9140 ext. 22502
  Chemistry Department                    fax  (905) 522-2509
  McMaster University
  Hamilton, Ontario, CANADA L8S 4M1.
___________________________________________________________________________

On Fri, 23 Nov 2001, Grzegorz Bakalarski wrote:

> -= This is automatically added to each message by mailing script =-
> [email-masked] -- To Everybody  | [email-masked] -- To Admins
> [email-masked] -- HELP CHEMISTRY or HELP SEARCH
> [email-masked] -- archive search    |    Gopher: gopher.ccl.net 70
> Ftp: ftp.ccl.net  |  WWW: http://www.ccl.net/chemistry/   | Jan: [email-masked]
>
>
>
>
>
>