Re: CCL:min. dist. between protons

 On 12 Dec 1994 KATEY-0at0-psipsy.uct.ac.za wrote:
 > I am working with Macromodel, and have the problem that it generates
 > structures in which the approach between two non-bonded hydrogens can
 > be as little as 1.76 Angstroms, and the energy of such interactions
 > is reported to be relatively low. I have used both the Amber force
 > field and the MM2 force field. I don't understand how such a close
 > interaction can have such a low energy. Can anyone please offer me an
 > explanation?
  Looks like your protons are connected to the same carbon (CH2 group). They
  could interact in force fields you have mentioned as so called "i -
 i+2"
  atoms, which have an artificial energy potential, having nothing similar
  to a real situation. This is an inherent flaw for any force field using
  flexible valence geometry. Do not pay attention to this "interproton
 energy"
  at all.
  Good luck.
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 Gregory V. Nikiforovich                                   Phone (314) 935-4677
 Research Professor                                        Fax   (314) 935-4979
 Center for Molecular Design                            E-mail address:
 Washington University
 gregory-0at0-wucmd.wustl.edu
 Lopata Hall, Box 1099
 St.Louis, MO 63130
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