Subject: Back ground charges in G94

From: "Emadeddin Tajkhorshid" <[email-masked]>
Date: Sun, 18 Aug 1996 15:30:33 -0600

Dear all

G94 is able to include background charges in single point calculation and this
option is not available for geometry optimization. On the other hand a few days
ago we had some messages in the list:

>     Gaussian94 is not supposed to optimize in uniform electric field
>also, but in fact it does. Keeping this in mind, I run optimization with
>background point charges. The first step seemed to work fine, generated
>new geometry and derivatives, etc. Nevertheless, at the second step point
>charges disappeared and eventually the geometry converged back to where I
>started. I suspect, Gaussian94 does not pass the information about
>point charges to some COMMON blocks, so they do not survive at the
>following steps of optimization route.

My question is that if it is able to calculate the derivatives in first step,
then what is the reason that CHARGE option is only available for single point
calc. Because in my eyes the problem of writing and reading background charges
in checkpoint file was not too hard to the people in Gaussian to be solved. If
so, please let me know.

Thanx in advance

-- 
Emad
*********************************************************************
E. Tajkhorshid				
German Cancer Research Center; DKFZ  Tel: +49 6221 42 2339
Dept. Molecular Biophysics (0810)    FAX: +49 6221 42 2333
P.O.Box 101949			     Email: [email-masked]
69009 Heidelberg, FRG
*********************************************************************
* It is nice to be important, but it is more important to be nice!  *
*********************************************************************