Le 24/01/12 09:33, pw_forum-request at pwscf.org a ?crit : > ------------------------------ > > Message: 2 > Date: Tue, 24 Jan 2012 11:49:00 +0530 (IST) > From: Niharika Joshi<joshiniharika20 at yahoo.in> > Subject: [Pw_forum] Occupied states in XAS > To: "pw_forum at pwscf.org"<pw_forum at pwscf.org> > Message-ID:<1327385940.93549.YahooMailNeo at web95709.mail.in.yahoo.com> > Content-Type: text/plain; charset="iso-8859-1" > > Hello, > > In the xspectra calculation, the option 'cut_occ_states=.false.' will include > the occupied states in XAS. > Why should one consider occupied states in absorption spectra because the > transitions are only to empty states. Or have understood it wrong? > ?-Niharika Joshi
Dear Niharika, of course in XAS only empty states are measured. However plotting occupied states could be useful for low energy features (pre-edge region). When for example there is not a clear large gap, it can be difficult to isolate empty from occupied states. This is the case in metals or small gap systems. So it can be useful to look at the full spectrum and see where the Fermi level is located. M. > (Project student, Indian Institute of Science Education and Research, Pune, > India) > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > http://www.democritos.it/pipermail/pw_forum/attachments/20120124/bccced8d/attachment-0001.htm > > ------------------------------ > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > > End of Pw_forum Digest, Vol 55, Issue 39 > **************************************** -- * * * * Matteo Calandra, Directeur de Recherche (DR2) Institut de Min?ralogie et de Physique des Milieux Condens?s de Paris Universit? Pierre et Marie Curie, tour 23, 3eme etage, case 115 4 Place Jussieu, 75252 Paris Cedex 05 France Tel: +33-1-44 27 52 16 Fax: +33-1-44 27 37 85 http://www.impmc.jussieu.fr/~calandra
