Subject: Bond Order Revisited

From: Pat Walters <[email-masked]>
Date: Tue, 3 Oct 1995 09:29:05 -0400 (EDT)

Dear Netters,

I guess I wasn't clear in my request for bond order algorithms.  I am
not interested fractional bond orders or natural bond orders.  I would
like to be able to simply assign single, double and triple bonds in a
molecule.  

Wally Reiher sent me the following excerpt from the DGEOM 95 release notes: 
     New Features
     *  Automatic connectivity generation and double bond assignment (even
     for conjugated and aromatic systems).  This eliminates the need for
     supplying CONECT records and/or editing them to specify double bonds
     for most organic structures, including peptides and nucleotides. 
     Automatic connectivity generation will be performed if CONECT records
     are missing. 

This is exactly what I want to do.  Apparently the routines in DGEOM 95
are adapted from a program called PSSHOW by Eric Swanson.  I would like to
know if anyone knows of a paper describing how this method works.  I'd also
like to hear from anyone who could tell me more about PSSHOW.

Any other relevant information would also be appreciated.

Anything I learn will eventually end up in Babel and everyone will be able
to use it.

Thanks in advance,

Pat

------------------------------------------------------------------ 
W. Patrick Walters, Ph.D. Scientist, Computational Chemistry and Molecular
Modeling Vertex Pharmaceuticals, Inc., 40 Allston St., Cambridge, MA 02139
Voice: (617)576-3111 FAX: (617)576-2109