Subject: SCF convergence and SCI-PCM using G98

From: Paulo Couto <[email-masked]>
Date: Mon, 3 Apr 2000 13:32:28 +0100

Greetings All

I am trying to run geometry optimization calculations on water clusters (
n=1-6 ),
using G98 at the HF/6-311++G** theory level with the SCRF=SCIPCM option and
water as solvent.
The problem is that SCF's don't converge at all.
Can anyone suggest a better parametrization to this method or an alternative
method
to simulate solvation effects at this theory level?
References are also welcome.

##########
Sample input for single center method, for the water molecule, using a
special grid:

#P RHF/6-311++G** SCF=(tight,MaxCycle=512) GUESS=always TEST
#OPT=(MaxCycle=100) SCRF=(SCIPCM) NOSYMM TEST

...

78.39 0.0004 434 1 2
############

I also tried the multicenter method with default parametrization and
different
sets of integration points. The result is the same: no SCF convergence.

Thanks in Advance

Paulo Couto
([email-masked])