Subject: Re: CCL:crystal packing calculations and programs

From: jerry perlstein <[email-masked]>
Date: Tue, 04 Feb 1997 11:37:41 -0800

Leslie Glasser gave some references to crystal packing in response to

Doug Smith's query, to which I would add the following additional

references:

A. Gavezzotti and G. Filippini JACS 118, 7153 (1996)

A. M. Chaka et al. Acta Cryst. B52, 165 (1996)

B. B. P. van Eijck et al. Acta Cryst. B51, 99 (1995)

J. Perlstein, JACS 116, 11420 (1994)

A. Gavezzotti, Acc. Chem. Res 27, 309, (1994)

W. Linert and F. Renz J. Chem. Inf. Comput. Sci. 33, 776 (1993)

H. R. Karfunkel and F.J.J. Leusen Speedup Journal 6, 43,(1992) good luck

finding this one, but it's quite good.

Douglas A. Smith  also wrote:

> What are the options when one does not have the crystal structure available?

> Can one reasonably start from a high quality ab initio calculation on a

> single molecule (gas phase) and use that structure to pack a crystal?

Generally no. The gas phase strucuture will be a local minimum but not

necessarily the minimum seen in the crystal structure. You need only

look at molecules which crystallize in different polymorphs to convince

yourself of this. See A. Gavezzotti and G. Filippini, JACS 117, 12299

(1995) for a long list of these.

Also as pointed out by Leslie, even if you get the correct molecular

local minimum to start with, you still don't know the space group to

use. Again since organic crystals are polymorphic, there will usually be

more than one space group.

> What packages are out there, commercial and "public domain" (free, QCPE,

> etc.) that can perform crystal packing calculations?  

There are a number of packages; in no particular order:

 1)PCK83 QCPE program no. 481 by D. J. Williams and also sold

commerically by Williams

2)C2-POLYMORPH by Leusen and Karfunkel. A module for the Cerius2

molecular modeling package from MSI

3)PACK by J. Perlstein, a module for the CHEMX/CHEMLIB molecular

modeling package from Chemical Design, Inc.

4)PROMET by A. Gavezzotti

None of the packages are capable of predicting space groups and most of

them cannot handle more than 1 or 2 single bond rotations. (PACK can

handle about 12 for monolayer crystal structures. If you get the
monolayer correctly, you can get the rest of the crystal packing.)

-- 
**************
Jerry Perlstein
Center for Photoinduced Charge Transfer
Department of Chemistry
University of Rochester
Rochester,NY 14627-0216
Tel: (716)275-2511
FAX: (716)242-9485
[email-masked]
http://stcoff.chem.rochester.edu/perlstein.html