Subject: Scan Massage ?

From: Harald Svedung <[email-masked]>
Date: Tue, 5 Oct 1999 19:12:19 +0200 (MDT)

Hi everyone!

I'm trying to make as accurate calculations as possible on the 
interaction potentials between "atoms in molecules". I wish to make some 
BSSE-correction on some potential scans.

I've tried the following for the colinear F2-F2 interaction:

#RMP2/AUG-cc-pVTZ Scan Massage Test      

F-F F-F  scan r2 

0 1
F1
X1 F1 1.
F2 F1 r1 X1 90.
F3 F1 r2 X1 90. F2 180.
X2 F3 1. F1 90. X1 180.
F4 F3 r1 X2 90. F1 180. 
        Variables:
r2 1.10350222 6 0.1379377775 
r1 1.40120372

3 Nuc 0.0
4 Nuc 0.0

as I want to use the basisfunctions on the second F2-molecule without the 
atoms to get a "maximum" correction for BSSE.

Initially Gaussian seams to read this as taking away the second 
F2-molecule
(output confirms 18 electrons), but when it comes to the scan it is 
confused regarding the numbering of the atoms and takes away not 
the second F2-molecule, but the F3 and X2 in the Z-matrix above.
This results according to output in an odd number of electrons and thus 
a conflict with multiplicity.

Is there a quick way arround this problem, some trivial keyword thing 
that I've missed or is this atom numbering missmatch in Gaussian a 
really unfortunate "feature"?  

All help is really welcome.
yours :-)
/Harald

Harald Svedung (Ph.Lic.)                phone:          +46-31-7722816
Department of Chemistry                 fax:            +46-31-167194
Physical Chemistry                      home phone:     +46-31-240897, +46-709223206	
Goeteborg University                    home e-mail:    [email-masked]
SE-412 96 Goeteborg, Sweden             www.che.chalmers.se/~svedung/