Optimization of 2D molecules

From: Genzo Tanaka <tanaka at.at ahpcrc.org>
Subject: Optimization of 2D molecules
Date: Mon, 24 Mar 2003 15:49:03 -0500

Hi all,
 I encountered several times the floating point exception (signal 8)
 error for optimization of linear and/or flat molecules (CO2, naphthalene
 analogs) in Gaussian 98 on Cray T3E. Methods included PM3 as well as DFT
 (b3lyp/6-31G*).
 For CO2, we can fix the angle to 179.999..., but it is not a good idea.
 Does anybody know how to work around this?
 Your suggestions are welcome.
 Thanks,
 Genzo Tanaka