CCL: force calculation on mopac



 Sent to CCL by: "Tony Yuan" [TYuan(-)cambridgesoft.com]
 See http://forum.chemih.com/forum/view.asp?aid=664&cid1
 [edited by jkl*ccl.net to remove winmail.dat]
 -----Original Message-----
 From: Gon alo Justino goncalo.justino * zmail.pt
 Sent: Sat 3/4/2006 6:35 PM
 To: Tony Yuan
 Subject: CCL: force calculation on mopac
 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