Subject: ab initio bond minimizations

From: [email-masked] (Ray Crawford)
Date: Mon, 14 Oct 1996 22:20:31 -0400

Howdy all --

        I have a rather unique problem.  I have a structure which was
resolved from an electron density map.  I wanted to compare this structure
to another but when I went to do so using ab initio methods, I found that
the single point energy of this molecule was horrendously large and any
attempts to do energetic geometry minimizations led to different structures
(changed torsions and bond angles).  Further investigation led me to the
conclusion that the main problem is that the errors in bond lengths (as
small as they were) were drowning out the effects which I wanted to see the
energetic changes for (torsional and angular changes).  I recently saw a
paper about a topic similar to this (I think it was in the Journal of
Computational Chemistry)...  If anyone has any references to work in this
area or any ideas about how I can go about comparing these structures, I
would appreciate it if you passed it on...  All information will be promptly
summarized and resubmitted...

                Thanks,
                        Ray Crawford
                                                               "Absence of
proof is not
                                                                 proof of
absence..."
                         [email-masked]                       -Richard Levine
                        http://w3.one.net/~iguana             The Lost World
                                                                            
     Micheal Crichton