From owner-chemistry@ccl.net Wed Dec 22 18:32:00 2010 From: "Serge Gorelsky gorelsky=-=gmail.com" To: CCL Subject: CCL:G: Calculation absorption spectrum using Gaussian G03 Message-Id: <-43449-101222175248-3434-8lIYfrNdvhtHlwjf2AkuRA(!)server.ccl.net> X-Original-From: Serge Gorelsky Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Date: Wed, 22 Dec 2010 17:52:41 -0500 MIME-Version: 1.0 Sent to CCL by: Serge Gorelsky [gorelsky]=[gmail.com] Negative excitation energies in TD-DFT calculations mean that there are lower energy electronic states relative to the "reference" electronic state. This is one of the tests to determine whether or not the reference state is the true ground state: if there are negative excitation energies, the reference state is NOT the ground state. On Wed, Dec 22, 2010 at 11:59 AM, Pilar Constanza Suarez pcs_3++hotmail.com wrote: > > Sent to CCL by: "Pilar Constanza Suarez" [pcs_3::hotmail.com] > Dear All. > > We try to calculate the UV-VIS absorption spectra of one gold atom whit > multiplicities 1 (ground state),3 y 5 using Gaussian 03 (Geometry optimization > of these molecules was obtained using b3pw91 method). > > The simulations to calculate absorption spectrum finished without errors but > when I checked the output files with AGUI the excitation energy values for gold > atom with multiplicities 3 and 5 are NEGATIVES. > > So I would like to know why these values are negatives and what it means? > > Also what happens if the calculation (UV-VIS absorption spectra) starts from an > excited open shell state? > > Thank you. > > Pilar.>      http://www.ccl.net/cgi-bin/ccl/send_ccl_message>      http://www.ccl.net/cgi-bin/ccl/send_ccl_message>      http://www.ccl.net/chemistry/sub_unsub.shtml>      http://www.ccl.net/spammers.txt> > > -- Best regards,   Serge Gorelsky