From chemistry-request@ccl.net Fri Jan 24 09:49:20 1992
Date:         Fri, 24 Jan 92 14:54:02 GMT
From: De windt <DEWINDT%VMSAC@OHSTVMA.ACS.OHIO-STATE.EDU>
Subject:      geometry optimization problems with the GAUSSIAN 90
To: CHEMISTRY@ccl.net
Status: R


I am a "gaussian 90" user, and I have encountered several problems
when trying to run geometry optimizations on molecular structures
involving transition metals with other lighter atoms. These difficul-
ties remained even after beginning with a numerical computation of
second derivatives in place of the classical unit hessian. Typically
the optimization goes pretty well at the beginning, until a fatal
point where the displacements are zero and remain so, though forces
are far from being negligible (around a factor of 10 above the threshold
) restarting the whole thing at the stopping point often provides with a
new "promenade" on the potential surface, and the same disappointing
result at the end, sometimes at a different point.
...Mayday...

Thank you very much in advance, and happy new year...

address: KRYS at FRSAC11.BITNET