Re: [Ifeffit] Energy shift (???)

Hi eunsuk1986 (unfortunately you did not share your full name with us...) I had some trouble with reading your feff.inp. Nevertheless the problem of the absolute alignment of FEFF xmu and experimental data has been the subject of earlier questions. I' am citing form a list contribution of J. Rehr (Aug 3rd 2003): "The FEFF calculation of the absolute energy is not meant to be highly accurate, and errors of several eV for K-shells of large Z atoms are not unusal. Thus you did nothing wrong in the input file. To match FEFF and experiment you *always* have to shift the FEFF absolute threshold to match experiment.". There is no way (I am aware of) to tell FEFF do this absolute shift (you can and you often need to shift the position of the Fermi level though) but you can do this with every plot program. Thus you should not worry too much about the absolute energies in your xmu but a lot about relative energies (i.e. the positions of the single resonances). HTH Jakob ___________________________________________________ Jakob Frommer Soil Chemistry Group Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich Universitätstrasse 16, CHN F19 CH - 8092 Zürich Tel: +41 44 632 87 58 Fax: +41 44 633 11 18 web: http://www.ibp.ethz.ch/research/soilchemistry ________________________________ From: ifeffit-bounces@millenia.cars.aps.anl.gov on behalf of ifeffit-request@millenia.cars.aps.anl.gov Sent: Mon 8/18/2008 09:46 To: ifeffit@millenia.cars.aps.anl.gov Subject: Ifeffit Digest, Vol 66, Issue 9 Send Ifeffit mailing list submissions to ifeffit@millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request@millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner@millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Energy shift (???) ---------------------------------------------------------------------- Message: 1 Date: Mon, 18 Aug 2008 16:46:26 +0900 From: ??? Subject: [Ifeffit] Energy shift To: Message-ID: Content-Type: text/plain; charset="ks_c_5601-1987" Hi everyoneI am studying XANES at Zn K-edge in ZnO nanocrystal by using FEFF8. I wrote FEFF8 as following, and got xmu.dat. I found that there was a difference between experimental data and xmu.dat (check file) for the energy. I dont understand why the energy is shifted. I wish to adjust xmu.dat in FEFF8 to my experimental dat. If someone knows how to do, please contact me. * -- * -- * -- * -- * -- * -- * -- * -- * -- * -- * -- * -- * -- * -- * TITLE name: zincite ZnO TITLE formula: ZnO TITLE sites: Zn1,O1 TITLE refer1: wyckoff, vol 1, ch III, p 111 TITLE refer2: TITLE schoen: TITLE notes1: EDGE K S02 1.0 * pot xsph fms paths genfmt ff2chi CONTROL 1 1 1 1 1 1 PRINT 1 0 0 0 0 0 * r_scf [ l_scf n_scf ca ] SCF 5.03864 0 15 0.1 * ixc [ Vr Vi ] EXCHANGE 2 0 0*EXAFS*RPATH 9.07729 * kmax [ delta_k delta_e ] XANES 4.0 ! 0.07 0.5 * r_fms [ l_fms ] FMS 5.53864 0 * *RPATH 0.10000 * emin emax resolution LDOS -20 20 0.1 POTENTIALS * ipot z [ label l_scmt l_fms stoichiometry ] 0 30 Zn -1 -1 0 1 8 O -1 -1 1 2 30 Zn -1 -1 1 ATOMS 0.00000 0.00000 0.00000 0 Zn1 0.00000 0.00000 0.00000 2.06302 1 O1 2.06302 -1.95951 0.00000 -0.65148 1 O1 2.06497 0.97978 -1.69700 -0.65148 1 O1 2.06500 0.97978 1.69700 -0.65148 1 O1 2.06500 0.97978 -1.69700 -2.71450 2 Zn1 3.34788 0.97978 1.69700 2.71450 2 Zn1 3.34788 0.97978 1.69700 -2.71450 2 Zn1 3.34788 0.97978 -1.69700 2.71450 2 Zn1 3.34788 _________________________________________________________________ ???? ???, ???? ?? ???? ???? ??? Windows Live Hotmail! ?? ???? ???! http://www.hotmail.com http://www.hotmail.com/