ab initio bond minimizations

 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..."
                          iguana |-at-| one.net                       -Richard
 Levine
                         http://w3.one.net/~iguana             The Lost World
      Micheal Crichton