Subject: CCL: onoim in g03

From: Steve Williams <willsd(at)appstate.edu>
Date: Tue, 06 Apr 2004 14:50:07 -0400

I am trying to learn to do onoim calculations in g03.  My test molecule is 
a rather large Re(V) complex that is a +2 singlet cation.  I am trying a 
two layer oniom with the Re and the 6 atoms it is bound to (1 N, 4 P, 1 Cl) 
as the high layer (b3lyp/lanl2dz) with the rest done at am1.  I found that 
the default guess did not work (stopped with an error before guess 
computation began) so switched to guess=harris and got rid of that 
error.  I now have persistent bad file IO crashes.  These usually indicate 
lack of disk space, but I do not think that is the case on this machine as 
I have been able to run some rather large CAS calculations, and single 
layer calculations run fine (b3lyp/lanl2dz on whole complex is slow but 
does run; geometry optimizations eventually converge...); none of these 
large calculations required any fooling with maxdisk.  I am running on a 64 
bit Itanium cluster so splitting rwf file has not been needed with other 
jobs.  The top of my input is below:

%mem=120MW
%nproc=4
# opt oniom=(rb3lyp/lanl2dz:ram1) geom=connectivity guess=harris

first try at oniom calculation for one of grant's biggies

2  1  2  1  0  1
  C                0    9.649231   -0.243106   -0.297205 L
  C                0    8.621088   -0.302810   -1.225543 L
  C                0    7.252282   -0.215031   -0.805502 L

with lots more geometry below.  G03 does seem to read this file as intended 
(it confirms which atoms are in the high and low layer, confirms that the 
whole molecule is a +2 singlet, that the high layer is a +2 singlet, and 
that the low layer is a neutral singlet.  The last few lines before G03 
crashes are :

  ONIOM: Cut between C /H   120 and P    26 factor= 0.773169 0.773169
  ONIOM: saving gridpoint 17
  ONIOM: generating point  3 -- low level on real system.
  Standard basis: VSTO-3G (5D, 7F)
  Atomic number  75 exceeds maximum of  54 in STO -- maximum used.
  There are   349 symmetry adapted basis functions of A   symmetry.
  Integral buffers will be    131072 words long.
  Raffenetti 1 integral format.
  Two-electron integral symmetry is turned on.
    349 basis functions,  1047 primitive gaussians,   349 cartesian basis 
functions
    179 alpha electrons      179 beta electrons
        nuclear repulsion energy      5857.5087847753 Hartrees.
  NAtoms=  130 NActive=  130 NUniq=  130 SFac= 1.00D+00 NAtFMM=   60 Big=T
  FileIO operation on non-existent file.
FileIO: IOper= 2 IFilNo(1)=  -516 Len=       61075 IPos=       61075 
Q=*****************

  dumping /fiocom/, unit = 1 NFiles =    51 SizExt =    524288 WInBlk 
=      2048
                    defal = T LstWrd =     4567040 FType=2 FMxFil=10000

  Number           0        501        502        503        507        508 
        511        520
  Base       4167680     432128     448512     600064     610304    3831808 
    1906688    3848192

Then there is good bit of related (diagnostic?) stuff.

Can anyone help me debug this oniom job?  I realize that this has almost 
certainly appeared on CCL in the not too distant past, but CCL searches are 
currently disabled so I have not been able to find those messages.

Thanks in advance for any help...
Steve

Steve Williams
A. R. Smith Department of Chemistry
Appalachian State University
Boone, NC 28608
USA
828-262-2965