Subject: Generating classical force field parameters for arbitrary molecules.

From: [email-masked] (Dr. Mike Gilson)
Date: Thu, 20 Oct 1994 14:12:55 -0400

I'd be grateful for pointers to software and/or journal references
relating to the problem of generating reasonable classical force-field
parameters (bond-stretch and angle-bend force constants, dihedral
rotation barriers, atomic charges...) for arbitrary organic molecules
of perhaps 100 atoms.  

Thanks in advance,

Mike Gilson
[email-masked]

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From: "Ben Burke" <[email-masked]>
Date: Thu, 20 Oct 1994 13:32:01 -0700

> rotation barriers, atomic charges...) for arbitrary organic molecules

===POINTER====>   "Molecular Mechanics Force-Field Parameterization
Procedures",                    AJ Hopfinger & RA Pearlstein, JCC, 5, No. 5,
486-99 (1984).
This is a set of procedures and guidelines for estimation of bond length, bond
angle and torsional potential constants for molecular mechanics force fields.
 The force field constants are ultimately derived by "subtracting" non-bonded
molecular mechanics energies from the molecular orbital energies using a model
compound containing the chemical structure to be parameterized.

===POINTER====>   "A Molecular Mechanics Valence Force Field for Sulfonamides
   Derived by ab Initio Methods", JB Nicholas et al, JPhysChem, 1991, 95,
9803-11 is a recent example of the method.  John's work is very nice, and
complete.
His model compound also reminds us that inversion about nitrogen is an
important consideration.

There are, of course, alternate techniques which involve frequency
calculations. I trust that others will be sharing expertise on this.

--Ben

-- 
[email-masked]        Tel: (619) 622-3018         FAX: (619) 622-3299 ----------------------------------------------------------------------------
Benjamin J. Burke        Research Scientist	     Computational Chemistry     
Agouron Pharmaceuticals	 3565 General Atomics Court  San Diego, CA     92107 
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