From owner-chemistry@ccl.net Mon Sep 3 04:57:01 2012 From: "mariusz.radon|a|gmail.com" To: CCL Subject: CCL:G: atomic spin densities Message-Id: <-47522-120903045501-1950-2vasMp3RUHLwpnQKvALTKA^^^server.ccl.net> X-Original-From: mariusz.radon[*]gmail.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=utf-8 Date: Mon, 3 Sep 2012 10:54:24 +0200 Mime-Version: 1.0 (1.0) Sent to CCL by: mariusz.radon[A]gmail.com Hi, What Gaussian calls "spin densities" are, in fact, spin populations. Take care, Mariusz Radon Dnia 2 wrz 2012 o godz. 14:40 "Marcin Sterniczuk m.sterniczuk*ichtj.waw.pl" napisaÅ‚(a): > > Sent to CCL by: "Marcin Sterniczuk" [m.sterniczuk],[ichtj.waw.pl] > Hello, > > I`m user of Gaussian program and I have a question about "Mulliken atomic spin densities". In quantum chemistry we have: spin densities and spin population. In Gaussian output the "Mulliken atomic spin densities" have not a units, summary spin densities for all atoms in molecule is equal 1. I think that the spin desnities shuld have a units. So what is unit of this parameter in Gaussian output? It is really spin densities? mayby it is spin population of unpaired electron?> > From owner-chemistry@ccl.net Mon Sep 3 12:53:00 2012 From: "MOREAU Yohann 224609 yohann.moreau=cea.fr" To: CCL Subject: CCL:G: atomic spin densities Message-Id: <-47523-120903034133-25154-lYYe+nkar0CQanm3h32qew ~~ server.ccl.net> X-Original-From: MOREAU Yohann 224609 Content-ID: Content-Language: fr-FR Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="iso-8859-1" Date: Mon, 3 Sep 2012 07:41:25 +0000 MIME-Version: 1.0 Sent to CCL by: MOREAU Yohann 224609 [yohann.moreau{:}cea.fr] Hi Marcin, Actually, by default, Gaussian outputs spin populations. They are computed as the difference between alpha and beta electron populations (Mulliken scheme). Hence, they are partial numbers of electrons. However, it is possible to compute spin densities (which is a number of electrons per volume unit). A way to get a representation of the spin densities is to generate a cube file with keyword spin (see the related documentation of gaussian), you will be able to visualize it as an iso-surface. I hep this has helped to clarify things. Best Regards, YM -- Yohann Moreau Maître de Conférence, Université Joseph Fourier iRTSV/CBM/MCT, CEA Grenoble 17 avenue des Martyrs 38 054 Grenoble Cedex 09 Tel. : (33) 4 38 78 29 62 Fax : (33) 4 38 78 54 87 Le 02/09/12 14:40, « Marcin Sterniczuk m.sterniczuk*ichtj.waw.pl » a écrit : > >Sent to CCL by: "Marcin Sterniczuk" [m.sterniczuk],[ichtj.waw.pl] >Hello, > >I`m user of Gaussian program and I have a question about "Mulliken atomic >spin densities". In quantum chemistry we have: spin densities and spin >population. In Gaussian output the "Mulliken atomic spin densities" have >not a units, summary spin densities for all atoms in molecule is equal 1. >I think that the spin desnities shuld have a units. So what is unit of >this parameter in Gaussian output? It is really spin densities? mayby it >is spin population of unpaired electron?> >