[Wien] QTL quantization axis for Y_lm orbitals

[Peter Blaha]

Well, I'm not sure I do understand all your problems, but a few comments:

a) XMCD is implemented in   optics !

b) I do not see the problem with A_lm, B_lm C_lm,..., because in any 
case  A_lm (or for semicore a C_lm) will dominate and you can probably 
neglect the B_lm and the corresponding u-dot radial function.

When you chose a good expansion energy for your radial wf., you more or 
less have this "hydrogenic orbital" with one fixed radial function. Of 
course, this argument holds only when your states are "localized", 
otherwise you will have a large interstital (PW) contribution.

c) I'm not the real expert of Wannier functions, but I guess the WF 
might be complicated linear combinations of different l,m ....



Am 09.02.2023 um 15:46 schrieb pluto via Wien:
> Dear Sylwia, dear Prof. Blaha, dear All,
>
> Having these A_lm, B_lm etc is of course a problem if one wants to 
> estimate interferences in dipole optical matrix element due to phases 
> at which different Y_lm orbitals enter the wave function. It would be 
> good to have a single complex number per Y_lm.
>
> For this it would be good to have the LAPW wavefunction projected onto 
> hydrogenic orbitals that just have a single radial component. Then 
> there would be just one complex coefficient. For a particular l (i.e. 
> s, p, or d) one would have a common radial part of the wave function, 
> since the radial part does not depend on m. Then one would need to 
> assume the final state expansion in Y_lm (can always be done even for 
> free-electron final state) and do some estimation of the XMCD process 
> within the simplified LCAO way of thinking.
>
> Is there any tool already existing to project WIEN2k wave function 
> onto hydrogenic orbitals?
> I was thinking something like this might be a part of the 
> WIEN2Wannier, but I wanted to ask here before investing further time 
> into this.
>
> Best,
> Lukasz
>
>
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Peter Blaha,  Inst. f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-158801165300
Email: peter.blaha at tuwien.ac.at
WWW:   http://www.imc.tuwien.ac.at      WIEN2k: http://www.wien2k.at
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