From chemistry-request \\at// ccl.net Fri Jul 26 12:24:15 1991
Date: Fri, 26 Jul 1991 12:13 EDT
From: "DOUGLAS A. SMITH" <FAX0236 # - at - # uoft02.utoledo.edu>
Subject: Re: Reply to "MOPAC6.0 geometry optimization"
To: zheng \\at// retina.chem.psu.edu
Status: R

The default minimization routine in both MOPAC 5.0 and 6.0 is BFGS.  DFP has
been discounted as a tremendously useful method.  MOPAC 6.0 also has 
eigenvector following (EF), which was not in 5.0.

Your comment concerning the necessity to check that all optimization methods
etc. are the same is salient.

I don't believe that the isomer possibility is too viable.  We have done 
enough tests to believe that while you do find a stationary point at higher
energy, it is typically very unrealistic as far as real chemistry (at least
for our systems).

Doug Smith