[Wien] Calculating XPS spectra in Wien2k

[Peter Blaha]

No, as I said before, for transition state calculations I'd add the electron
into the background (case.inm), not to the valence electrons.

(In XPS you remove the electron from your system (while in XANES it stays in the solid)

Laurence Marks schrieb:
> And for an insulator when the extra 1/2 (or 1) electron goes into theconduction 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 a
lso 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 écrit :>>> 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, Commi
ssion 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 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
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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/
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