[Wien] XMCD for Mn

Peter Blaha pblaha at theochem.tuwien.ac.at
Mon Jul 15 13:51:34 CEST 2013


Yes, the ab initio simulation without any empirical parameters is a very 
tough problem.

You probably need both, something like BSE in order to account properly 
for the e-h interaction, but also some highly correlated method to deal 
with the interactions within the partially occupied d-shell.

We have seen that for MnO BSE alone is not really enough (although it 
improves compared to LDA+U core-hole calculations), and in particular 
the satelite beween L2/L3 is NOT coming out.

Clearly, standard DFT is not able to give these details.

Am 15.07.2013 10:44, schrieb Fecher, Gerhard:
> You have to couple the core hole with the open 3d shell, that is not possible with Wien, and I guess in none of the DFT codes.
>
> Check the work of Thole, van der Laan, de Groot (just search for them on Phys Rev) to learn about multipletts, then you will figure out what is going on in the spectra.
>
> Ciao
> Gerhard
>
> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> "I think the problem, to be quite honest with you,
> is that you have never actually known what the question is."
>
> ====================================
> Dr. Gerhard H. Fecher
> Institut of Inorganic and Analytical Chemistry
> Johannes Gutenberg - University
> 55099 Mainz
> ________________________________________
> Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at]" im Auftrag von "prasenjit roy [prasenjit1988 at gmail.com]
> Gesendet: Montag, 15. Juli 2013 10:37
> An: wien at zeus.theochem.tuwien.ac.at
> Betreff: [Wien] XMCD for Mn
>
> Dear Prof Blaha and Wien2K users,
>
>
>              Recently I was using Wien2k 12.1 for calculating the XMCD spectra of various systems. But it is well established that for Mn-atom the L23-XMCD signal has 3 peaks instead of 2. One example is shown here : (J. AM. CHEM. SOC. 2002, 124 , 9894-9898). The third peak generally found in between L2 and L3 peak, at 643 eV and has the same sign as L3 peak.
>              Now the problem I faced is described below. I used 1/2 core hole for Mn atom and a 2x2x2 supercell, but the third peak was missing. Since the value of local moment depends a lot on that peak, it is very necessary to reproduce the peak in WIEN2K. Some people described that the extra peak is originating from different valence state. So How can I obtain the correct spectra? Do I need to use Bethe-Salpeter equations for that purpose or something else?
>               I Will be very much thankful to yuo if you kindly give me some suggestions. Thank you very much.
>
> Your sincerely,
> Prasenjit Roy
> Electronic Structures of Materials
> Radboud University
> Nijmegen
> +31 (0) 24 36 52805
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-- 
Peter Blaha
Inst.Materials Chemistry
TU Vienna
Getreidemarkt 9
A-1060 Vienna
Austria
+43-1-5880115671


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