Subject: PCM OPT question

From: "Close, David M." <CLOSED :: mail.etsu.edu>
Date: Fri, 15 Apr 2005 11:11:06 -0400

CCLers:

  I am interested in optimizing a molecule in a PCM cavity.  I have no
problems in the gas phase with the following input for a G98
calculation:

  #B3LYP/6-31++G(d,P) opt scf=qc

  I can then run this as a single point calculation in a PCM cavity as

  #B3LYP/6-31++G(d,p) geom=checkpoint scrf(iefpcm, read) scf=tight

  However I cannot do an optimization with these keywords.  The solution
never converges.  I realized that I'm on a shallow PE surface when I was
doing

the gas phase calculations.  I found it helpful to use the quadatically
convergent procedure, scf=qc.  However when I try this under the OPT in
the PCM cavity,

the molecule is not in a PCM cavity?  No error messages appear.  But
there are no calculations of the surrounding cavity.  The program thinks
it is doing a PCM calculation as it prints out the dipole moment and the
quadrupole moment, but these are all zeroes.  

  Does anyone have a way to work around this.

  Thanks, Dave Close