From owner-chemistry@ccl.net Wed Nov 14 03:01:00 2012 From: "Michel Petitjean petitjean.chiral^gmail.com" To: CCL Subject: CCL: molecules in cylinders Message-Id: <-47877-121114025850-11477-8P/PoGpA6Jg0qXSWnPawmA##server.ccl.net> X-Original-From: Michel Petitjean Content-Type: text/plain; charset=ISO-8859-1 Date: Wed, 14 Nov 2012 08:58:43 +0100 MIME-Version: 1.0 Sent to CCL by: Michel Petitjean [petitjean.chiral**gmail.com] Dear CCLers, Molecules are often modelized by spheres, although few molecules are globular. A better model is a cylinder: either a minimal height cylinder for roughly flat molecules, or a minimal radius cylinder for roughly linear molecules. Other shape models exist, such as rectangular boxes, the smallest enclosing polyhedron, etc. But more the shape is sophisticated, more difficult it is to enter in modeling calculations. All the shape models above are calculated in the freeware RADI (see at the bottom of the page: http://petitjeanmichel.free.fr/itoweb.petitjean.freeware.html). The funny part of this story is that one of the most simple and useful models, i.e. the minimal radius cylinder, is easy to define but hard to compute. Anyway, I did the calculation. Best regards, Michel Petitjean MTi, INSERM UMR-S 973, University Paris 7, 35 rue Helene Brion, 75205 Paris Cedex 13, France. Phone: +331 5727 8434; Fax: +331 5727 8372 E-mail: petitjean.chiral- -gmail.com (preferred), michel.petitjean- -univ-paris-diderot.fr http://petitjeanmichel.free.fr/itoweb.petitjean.html