And for an insulator when the extra 1/2 (or 1) electron goes into the conduction band and E_F changes....?
On Wed, Sep 17, 2008 at 7:20 AM, Peter Blaha <pblaha at theochem.tuwien.ac.at> wrote: > It should be EF. I think experimentally binding energies in XPS are given > with respect > to EF=0. > The difference between EF and E_vacuum (i.e. the potential "VZERO" in the > middle of > a slab) gives the work function. > > Laurence Marks schrieb: >> EF of E_vacuum for the comparison? >> On Wed, Sep 17, 2008 at 12:58 AM, Peter Blaha<pblaha at >> theochem.tuwien.ac.at> wrote:> In addition to Xaviers comments:>> Yes, if >> you have eg. 2 oxygen atoms in your structure, the differences> in the core >> energies should reflect pretty well the experimentally> measurable >> core-level shifts.>> If you want to calculate the core energies better you >> can use> a) Slater's transition state> b) delta-scf calculations>> a) remove >> HALF a core electron from case.inc (add it to case.inm)> do an scf >> calculation. Now the (eigenvalue-EF) difference should be> closer to >> experiment (expect errors of a few eV instead of 30)> b) You can also use a >> full core hole and compare E-tot of groundstate> and excited state. >> Eventually this should be done in a supercell and> only on one of the atoms >> the hole should be added to avoid hole-hole> interactions.>>> Rocquefelte >> schrieb:>> Dear James,>>>> If you want to compare valence XPS spectrum with >> the DOS deduced from>> your Wien2k calculation, you will obt > ain a qualitative agreement.>> Concerning the core states, you may have > access to the energy of these>> states in the case.scfc file. These values > are relative to the fermi>> level given in the case.scf file.>> Thus you > should modify these energies in such a way to have a fermi>> level comparable > to your XPS experiment (the top of the valence).>>>> Here is an example based > on TiO2 rutile :>>>> - Energy of Ti 2p1/2 (2p* in scfc file) = -442.5 eV>> - > Energy of Ti 2p3/2 (2p in scfc file) = -436.7 eV>>>> - Energy of O 1s = > -504.2 eV>>>> These values should be compared to the following experimental > XPS>> binding energies (BE):>>>> - BE Ti 2p1/2 = 464.4 eV>> - BE Ti 2p3/2 = > 458.6 eV>>>> - BE O 1s = 530.1 eV>>>> So, as you can see, a strong deviation > (of about 30 eV) is observed>> between experimental and calculated data.>> > However, I would believed that the deviation is smaller if you compare>> > different BE in a same structure.>>>> Hope that this email will help you>>>> > Regards>>>> >>>>> James Enterkin a ?crit :>>> Dear All,>>>>>> I was wondering if anyone >>>>> would know how to go about calculating the>>> energy of an XPS peak?>>> I >>>>> have a converged structure, and would like to be able to calculate>>> the >>>>> binding energy of an electron on a specific atom in the structure,>>> to >>>>> see if it matches up with the shift in the experimental XPS of that>>> >>>>> same structure.>>> If anyone has previously done this or similar, or >>>>> knows what method>>> would be best to go about this, your suggestions >>>>> would be most helpful.>>>>>> Thank you,>>> Jim>>>>>> -->>> James A. >>>>> Enterkin>>> j-enterkin at nortwestern.edu <mailto:j-enterkin at >>>>> nortwestern.edu>>>> Ph.D. Candidate>>> K.R. Poeppelmeier and L.D. Marks >>>>> Groups>>> Department of Chemistry, Northwestern University>>> >>>>> ------------------------------------------------------------------------>>>>>> >>>>> _______________________________________________>>> Wien mailing list>>> >>>>> Wien at zeus.theochem.tuwien.ac.at>>> >>>>> http://zeus.theochem.tuwien.ac.at/mai > lman/listinfo/wien>>>>>>> _______________________________________________>> > Wien mailing list>> Wien at zeus.theochem.tuwien.ac.at>> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien> > _______________________________________________> Wien mailing list> Wien at > zeus.theochem.tuwien.ac.at> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien> >> >> >> -- Laurence MarksDepartment of Materials Science and EngineeringMSE Rm 2036 >> Cook Hall2220 N Campus DriveNorthwestern UniversityEvanston, IL 60208, >> USATel: (847) 491-3996 Fax: (847) 491-7820email: L-marks at northwestern dot >> eduWeb: www.numis.northwestern.eduChair, Commission on Electron >> Crystallography of >> IUCRwww.numis.northwestern.edu/IUCR_CED_______________________________________________Wien >> mailing listWien at >> zeus.theochem.tuwien.ac.athttp://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > > -- > > P.Blaha > -------------------------------------------------------------------------- > Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna > Phone: +43-1-58801-15671 FAX: +43-1-58801-15698 > Email: blaha at theochem.tuwien.ac.at WWW: > http://info.tuwien.ac.at/theochem/ > -------------------------------------------------------------------------- > > _______________________________________________ > Wien mailing list > Wien at zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > -- Laurence Marks Department of Materials Science and Engineering MSE Rm 2036 Cook Hall 2220 N Campus Drive Northwestern University Evanston, IL 60208, USA Tel: (847) 491-3996 Fax: (847) 491-7820 email: L-marks at northwestern dot edu Web: www.numis.northwestern.edu Chair, Commission on Electron Crystallography of IUCR www.numis.northwestern.edu/IUCR_CED
