Subject: Re: CCL:Intermolecular minimitation

From: [email-masked] (Peter Shenkin)
Date: Tue, 9 May 95 12:39:48 -0400

> From [email-masked]  Tue May  9 12:16:47 1995
> From: [email-masked] (Antonio Fernandez Ramos)
> Subject: CCL:Intermolecular minimitation

> I have a dimer intermolecular potential with several parameters; the
> variables are the distances between atoms. I want to optimize the
> intermolecular coordinates but keeping the intramolecular coordinates
> fixed, as well as two intermolecular coordinates, one angle and one
> distance.
> Is there any program available which will allow me to introduce the
> potential depending on the distances and the restrictions, and which
> will optimize the rest of the coordinates, and be easy to use?

The 5.0 version of BatchMin (part of the MacroModel suite of fine
programs) has facilities for this.

You would use FXDI commands to fix as many interatomic distances
as you please, then ASET commands to put each molecule into a set,
then the ASNT command to turn off all force-field interactions 
(but not the user-added constraint interactions) between the sets.

Once you've done this, you may blithely perform energy minimization,
conformational, search, MC, MD, etc., using your choice of MM2,
MM3, AMBER or OPLS force-fields, together with the GB/SA solvent 
model, if you so choose.  Coming soon:  MMFF (Merck Molecular Force 
Field).

	-P.
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