From owner-chemistry@ccl.net Wed Apr 29 11:31:01 2009 From: "Rzepa, Henry h.rzepa]^[imperial.ac.uk" To: CCL Subject: CCL:G: critical points and Density Message-Id: <-39203-090429101928-9894-8jz0uwivPcI6bYvMDI+YOw/a\server.ccl.net> X-Original-From: "Rzepa, Henry" Content-Type: text/plain; charset="us-ascii" Date: Wed, 29 Apr 2009 15:19:08 +0100 Mime-Version: 1.0 Sent to CCL by: "Rzepa, Henry" [h.rzepa*|*imperial.ac.uk] >Sent to CCL by: "miguel k escobedo" [kmiguelescobedo*|*yahoo.com] >Hey CCLers, > >I need to calculate the density and critical points, can someone give me an example of how to calculate these properties in gaussian. > The Gaussian code is old, and not maintained (this may still be the case in Gaussian 09). Instead, use eg http://aim.tkgristmill.com/ (AIMALL) or the commercial http://www.aim2000.de/ The former is largely text only, the latter more GUI/Visual. They mostly give the same results (but not always, for reasons too complex to note here). Miroslav Kohout has also written a program called DGrid, now at V 4.4 which also does ELF as well as rho(r) density analysis (again command line, not GUI driven). Finally, Paul Popelier has written Morphy; http://morphy.mib.man.ac.uk/ for which a small charge is levied and Bernard Silvi offers Topmod (http://www.lct.jussieu.fr/pagesperso/silvi/clark.html) although this has to be compiled first (i.e. no binaries). These programs take either a .wfn file (Gaussian keyword output=wfn) or the fchk file. One issue with all these programs (I have not tried Morphy in this context) is that none run in parallel mode, and for larger systems (say > 300 basis functions) they can be VERY slow (> 24 hours). From my point of view, a parallelized version running on eg 8-core systems would be a real breakthrough, enabling larger molecules to be analyzed. -- Henry Rzepa. +44 (020) 7594 5774 (Voice); http://www.ch.ic.ac.uk/rzepa/rzepa.xrdf (FOAF) http://www.ch.ic.ac.uk/rzepa/ Dept. Chemistry, Imperial College London, SW7 2AZ, UK. (Voracious anti-spam filter in operation for received email. If expected reply not received, please phone/fax).