From owner-chemistry.,at,.ccl.net Sat Mar  4 17:52:00 2006
From: "Gon alo Justino goncalo.justino * zmail.pt" <owner-chemistry(~)server.ccl.net>
To: CCL
Subject: CCL: force calculation on mopac
Message-Id: <-31107-060304174951-9344-NQrXYbYpA99BcMtNbUF9Vg(~)server.ccl.net>
X-Original-From: "Gon  alo  Justino" <goncalo.justino[*]zmail.pt>
Date: Sat, 4 Mar 2006 17:49:48 -0500


Sent to CCL by: "Gon  alo  Justino" [goncalo.justino*zmail.pt]
Dear all,

I recently upgraded to mopac 2002 built in ChemDraw for Windows. I'm trying to get a force calculation running but I'm stuck at this:

 - when I use AM1 GNORM=0.01 everything is ok, i get a nice output file; 
 - when I use AM1 FORCE I get back  ** GRADIENT IS TOO LARGE TO ALLOW FORCE MATRIX TO BE CALCULATED, (LIMIT=10) ** EITHER ADD 'LET' OR REDUCE GRADIENT   USING 'TS' OR OTHER GEOMETRY OPTIMIZER~
 - if I use AM1 FORCE TS, or AM1 FORCE LBFGS, I get back MORE THAN ONE GEOMETRY OPTION HAS BEEN SPECIFIED; CONFLICT MUST BE RESOLVED BEFORE JOB WILL RUN.

This happens for any molecule. Is this my incompetence, software conflict or simple mis-installation?

Any suggestion is welcome,

Gonalo Justino 
goncalo.justino[a]zmail.pt