Subject: Z matrix to cartesian coord. Question

From: "Charles G. James" <[email-masked]>
Date: Thu, 08 Dec 1994 14:27:17 -0500 (EST)

I do not mean this as an attack upon anyone or anything.  However this relates
to information I have to pass on to undergraduates in reference to
computational chemistry.  Just this week someone on this mailing list asked for
a way to get 10-15 (significant?) digits, after the komma(decimal), Cartesian
coordinates for a Ih symmetry molecule from the z matrix of a Gaussian
92 program. Are we at the stage where that many significant digits are given by
any computational chemistry method?  Are we at the stage where that many
significant digits are obtainable by any physical method used to measure
structure?  I am still warning undergraduates to beware of the number of digits
which can appear in calculations not connected to their measurements or their
original input.  Can I now say there are ways out there to get precision only
formerly dreamed by spectroscopist? Are there ways to get structural parameters
to this precision?

Charles G. James, Jr.           Assoc. Professor of Chemistry
Dept. of Chemistry,  University of North Carolina at Asheville
Asheville, NC 28804-3299, USA             Phone: (704)251-6443
FAX: (704)251-6041                     E-mail: [email-masked]