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/ --------------------------------------------------------------------------
