From owner-chemistry@ccl.net Mon Sep 26 04:37:00 2011 From: "Toomas Tamm tt-ccl2!A!yki.ttu.ee" To: CCL Subject: CCL:G: High virial ratio Message-Id: <-45518-110926043408-21855-uRlgOZSmmZU8pBEASO4SAQ#%#server.ccl.net> X-Original-From: Toomas Tamm Content-Transfer-Encoding: 7bit Content-Type: text/plain Date: Mon, 26 Sep 2011 11:33:36 +0300 Mime-Version: 1.0 Sent to CCL by: Toomas Tamm [tt-ccl2..yki.ttu.ee] On Fri, 2011-09-23 at 23:57 -0400, Sandhya Rai sandhyachemistry30*o*gmail.com wrote: > I am studying metal interactions with biomolecules. Some times I get > very high virial ratio like 4.09 etc. The frequency values are all > real and the output structures are also fine. Can any one suggest me > what might be going wrong. The metal I use is gold You do not say what method, basis set, or software you use, but assuming you use DFT with some common software such as Gaussian, you (or the software) probably have selected a pseudopotential (ECP) containing basis set for gold. If this is the case, the virial theorem indeed does not hold for your system. For an explanation, see, for example, http://www.ccl.net/cgi-bin/ccl/message-new?1997+01+30+016 -- Toomas Tamm e-mail: tt-ccl2 (at) kky . ttu . ee Chair of Inorganic Chemistry voice: INT+372-620-2810 Tallinn University of Technology fax: INT+372-620-2828 Ehitajate tee 5, EE-19086 Tallinn, Estonia http://www.kk.ttu.ee/toomas/