Subject: New molecular packing software

From: [email-masked] (D. E. Williams)
Date: Wed, 22 Nov 1995 12:59:16 -0500 (EST)

Mpa/mpg is a new suite of programs designed for molecular packing
analysis and molecular packing graphics in the unix environment.  The
capability of the mpa module extends from minimization of the energy of
association of two or more molecules (e.g., molecular clusters and
host-substrate docking) to energy minimization of a molecular assembly
in a crystal lattice of any space group symmetry (e.g., crystal polymorph
prediction).  The software is capable of predicting space groups and
reduced cells in which a given molecule may crystallize.  Provision for
limited molecular flexibility is made through selected rotations about
intramolecular bonds.  Molecular and/or crystal symmetry restrictions
may be selectively applied as desired.
	A library of commonly available intermolecular force fields is
included (e.g., WH86, MM85, Biosym, Charmm, Dreiding, etc.), and provision
is made for user supplied force fields.  The program selects energy
minimization by OREM (off-ridge eigenvector minimization), SD (steepest
descents), or NR (Newton-Raphson) as appropriate for the model.  All first
and second derivatives of the energy are calculated analytically; the
second derivative matrix (hessian) is diagonalized and its eigenvectors
determined.  Simulated annealing is included to aid in locating global,
rather than subsidiary, energy minima.
	The molecular packing graphics (mpg) module is closely integrated
with the molecular packing analysis module to give users fast, convenient,
and useful graphical visualization of the results.
	To obtain an abstract of the program and a listing of example
calculations, send an email request to [email-masked].