Z matrix to cartesian coord. Question

 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: james - at - unca.edu