Dear matteo, Thank you very much! I've got the picture now.
BTW, in my previous calculation, i mistakenly extract the core wavefunction from the pseudopotential WITH a core hole. But the result seems good when compared with the experiment. Does it happen often? Cheers, Min Wu 2010-10-5 >From: matteo calandra <matteo.calandra at impmc.jussieu.fr> >Reply-To: PWSCF Forum <pw_forum at pwscf.org> >To: pw_forum at pwscf.org >Subject: Re:[Pw_forum] problem with Xspectra >Date: Tue, 5 Oct 2010 10:49:48 +0200 > >Dear Min Wu, > > the pseudopotentials to be used for the absorbing atom >in Xspectra are those having >the label _gipaw, two examples are: > >Fe.pbe-sp-mt_gipaw.UPF >Fe.star1s-pbe-sp-mt_gipaw.UPF > >The first one has no core-hole and has full gipaw informations >while the second one has core-hole and full gipaw informations. >Gipaw informations mean many things. What you need to know is that >GIPAW informations include the presence of the >all-electron wavefunction for the 1s core state. > >Now when you run a simulation you first need to calculate the charge >density in the presence of a core-hole and thus use pseudo >Fe.star1s-pbe-sp-mt_gipaw.UPF . This is done by a standard pw.x >scf calculation using this pseudo. >In a second step you need to calcuate the Xanes cross >section and this is done by the Xspectra code. > >In the calculation of the matrix element appearing in the >Xanes cross-section (Fermi golden rule) the initial 1s state >IN THE ABSENCE of a core hole is needed. This information is contanined >in the pseudo potential WITHOUT the core hole (Fe.pbe-sp-mt_gipaw.UPF). >Thus you simply extract this wavefunction using the script given with the >Xspectra disribution and you put the name of the file produced by the script >in the input file of the Xspectra program. > >You cannot use the 1s core function with the core hole simply because this is >wrong as the matrix element inthe cross section involves the product >between the initial and final states and the initial state has no core hole. > >M. >> Message: 1 >> Date: Tue, 05 Oct 2010 00:42:50 +0800 >> From: "wumindt2" >> Subject: [Pw_forum] problem with Xspectra >> To: pw_forum at pwscf.org >> Message-ID: >> Content-Type: text/plain; charset="gb2312" >> >> Hi, >> >> I'm a new user of Xspectra. >> >> In the Xspectra example given in the pwscf code, it calculates the >> XAS using the pseudopotential >> without core hole level. In this case, we need to extract the core >> wavefunction from the GIPAW >> pseudopotential when we run the xspectra.x. >> >> Now there are pseudopotentials with core hole, normally named as >> *.star1s*.UPF. So here is >> my question, after the SCF calculation, do we still need to extract >> the core wavefunction from the >> peusopotential of the absorbing atom? >> >> If the answer is yes, then why we choose the core wavefunction from >> the pseudopotential as the ground >> state, rather than the core wavefunction after the SCF calculation? >> >> Thanks! >> >> Min Wu >> 2010-10-4 > > >---------------------------------------------------------------- >This message was sent using IMP, the Internet Messaging Program. > > >_______________________________________________ >Pw_forum mailing list >Pw_forum at pwscf.org >http://www.democritos.it/mailman/listinfo/pw_forum >
