[Wien] EELS of L3 Ti edge

[Philippe Moreau]

Dear Emil,

 i think you should be very careful in using WIEN for L3, L2 edges. Due 
to the strong coupling of p and d levels in transition metals, 
transition energies/ intensities are rather complex to get (some "L3" 
lines can appear at the "L2" positions) and this is not taken into 
account in WIEN. An agreement with experiment can only be fortuitous or 
in special cases (structureless edges). I think multiplet calculations 
are the best way to proceed (Racah program, de Groot).

best regards

P. Moreau



> Dear WIEN users,
>
> I’m doing experimental and theoretical research on EELS of Ti (oxides 
> mainly). I found big differences in the experimental and computed 
> spectra (for L3 edge) – the computed spectra look very, very far from 
> the experimental ones. We tried to include other orbitals in the 
> computation (changing the Ar core with Ne and even He) but without any 
> positive result. There are some articles in which is shown that the 
> expected ratio of the L3:L2 intensities should be 2:1 (on the basis of 
> 2j+1 degerancy). It looks like that this can be the reason for these 
> differences with the experimental results. In the same articles is 
> shown that the ratio L3:L2 has to be 0.8 and in this case the spectral 
> features in the computed and experimental spectra are quite similar 
> one to each other. My question is it is possible to change somehow 
> these ratios or how we can improve the quality of the spectra? I would 
> like just to notice, that in the case of Cr we don’t have such 
> differences - the computed spectra look quite good.
>
> Thanks in advance for your help
> Best regards,
> Emil Stoyanov
>
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-- 
Dr. Philippe MOREAU

Maître de Conférences à l'université de Nantes

Institut des Matériaux Jean Rouxel
Laboratoire de Chimie des Solides
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B.P. 32229
44322 NANTES Cedex 3
FRANCE

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