Subject: GVB calculation in Gaussian'98

From: "Demetrio A. da Silva Filho" <[email-masked]>
Date: Mon, 29 Apr 2002 13:02:55 -0300

Dear CCL'ers,

I am trying to perform a GVB calculation in Gaussian'98. The basic idea is 
to create
just one GVB pair taking one electron from HOMO-1 one from LUMO. All the 
orbitals below the pair
will be considered as closed shells and will not enter in the calculation. 
The system will be forced to be singlet.

I was able to run that calculation in GAMESS, but the results are not 
consistent, so
I want to do the same calculation in Gaussian'98. But I could not figure 
out which keywords I must use in order
to do  the same thing using Gaussian'98.

Using Gamess, I just need to run a Hartree-Fock calculation to have a guess 
for the orbitals
and then I use the keywords

$SCF NCO=88 NSETO=2 NO(1)=1,1 $END

To create the GVB pair and, freezing all orbitals below the HOMO and the 
keywords:

$GUESS  GUESS=moread norb=90 NORDER=1 $END
$guess iorder(88)=89 iorder(89)=88 $end

To change the HOMO-1 orbital (N=88) into HOMO (N=89).

Then, at the end, I will have just one GVB pair composed by an electron
> from HOMO-1 and one from LUMO.

Does anybody knows how can I do the same thing using Gaussian'98?

Thanks in advance and have a nice day!

Demetrio Filho