From owner-chemistry@ccl.net Mon Feb 22 01:47:00 2010 From: "Alexander Bagaturyants sasha .. photonics.ru" To: CCL Subject: CCL:G: G03 Temperature Parameter Message-Id: <-41309-100222013024-20321-JU78qJ+Oc2NfKQXR8nUM1Q%server.ccl.net> X-Original-From: "Alexander Bagaturyants" Content-Language: ru Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="ISO-8859-1" Date: Mon, 22 Feb 2010 09:30:09 +0300 MIME-Version: 1.0 Sent to CCL by: "Alexander Bagaturyants" [sasha:-:photonics.ru] Finally, we have got a correct answer to the question after some = misleading comments. There is an evident difference between quantum-mechanical values, which refer to a certain quantum-mechanical state, and thermodynamic values, = which refer to a thermodynamic ensemble (or, for an isothermal process, to a certain temperature). These simple statements must be known to any = student or novice researcher in quantum chemistry or molecular simulations.=20 However, this is so trivial that hardly deserves a discussion, and you should not be an expert to understand that. Prof. Alexander A. Bagatur'yants Photochemistry Center Russian Academy of Sciences ul. Novatorov 7a Moscow 119421 Russia Phone: +7(495)9362588 (office) +7(916)5317022 (mobile) Fax: +7(495)9361255 e-mail: sasha|-|photonics.ru=20 bagaturyants|-|gmail.com > From: owner-chemistry+sasha=3D=3Dphotonics.ru|-|ccl.net [mailto:owner-chemistry+sasha=3D=3Dphotonics.ru|-|ccl.net] On Behalf Of = Marcel Swart marcel.swart ~~ icrea.es Sent: Monday, February 22, 2010 1:08 AM To: Bagaturyants, Alexander A. Subject: CCL: G03 Temperature Parameter In any quantum-chemistry program, the temperature one can set on input = has effect mainly on the thermodynamic analysis, i.e. how the vibrational frequencies can = be transformed into enthalpy, entropy and free energy. The electronic energy, HOMO, LUMO, optimization, etc. are completely independent of the temperature.=A0 Please read a good introductory textbook like Jensen's "Introduction to computational=A0chemistry", or any one of the introductory textbooks (Szabo/Ostlund, McWeeny, Leach, Cramer, etc.). =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D dr. Marcel Swart ICREA Research Professor at Institut de Qu=EDmica Computacional Universitat de Girona Parc Cient=EDfic i Tecnol=F2gic Edifici Jaume Casademont (despatx A-27) Pic de Peguera 15 17003 Girona Catalunya (Spain) tel +34-972-183240 fax +34-972-183241 e-mail marcel.swart*|*icrea.es marcel.swart*|*udg.edu web http://www.marcelswart.eu =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D