[Wien] txspec

[Peter Blaha]

> I am trying to calculate the Pt L2-edge x-ray absorption spectrum. I have several questions.
>
> 1. In UG, if I set appropriately nonzero 'SPLIT', then I can get a spectrum in which the L2- and L3-edge are split. However, I tried SPLIT=30, I got almost the identical L2- and L3-edge spectra. What is wrong? It shows some difference, but the difference is not due to the L2- and L3-edge. The difference is due to two transitions, l->l+1 and l->l-1.
>
> 2. In SRC_txspec directory, I checked the 'txspec.f' file. In the 'txspec.f' file on the line 95, it is said that 'just take the negative kappa.' I think the parameter 'kappa' is a quantum number that is determined by the total angular momentum (j=l+s). In order to calculate the L2-edge, I set n=2, l=1. Then the 'txspec.f' file autimatically select kappa=-3, which corresponds to j=3/2, i.e., L3-edge. Am I correct?
>
> 3. Since I think that the negative kappa corresponds to the L3-edge, I tried to change the line 96 of the 'txspec.f' file from 'kappa=-1-LC' to 'kappa=LC' to calculates the L2-edge, however, it does make almost no difference. Then I checked which program would use the paramete 'kappa.' It is used only in the 'hfsd.f' file. In the 'hfsd.f' file it is used to check only it the choices of NATT and NC are correct. I mean the parameter kappa is practically never used. Why?

XSPEC does NOT use any relativistic selection rules,.....

SPLIT is most useful for "lighter" elements, where the core state is
splitted by a few eV only and the L2 and L3 spectra "overlap".
SPLIT does not do anything else than taking the non-relativistic spectrum,
and overlaps two identical spectra (with specified intensities) shifted by
SPLIT.

You can add SO also for the valence states, work out the selection rules
yourself and choose the appropriate partial DOS (maybe using the QTL
program) for "fully relativistic spectra.

Regards
                                      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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