[Wien] QTL quantization axis for Y_lm orbitals

gutowska at agh.edu.pl gutowska at agh.edu.pl
Thu Feb 16 14:44:16 CET 2023


Dear Łukasz,

every second column is a small component of relativistic wave function. 
You should  multiply it by alpha=1/137 in case of relativistic 
calculations, otherwise you should neglect it. For reference, you can 
look into eg. l2main.F, where eg. overlaps are  calculated as:
             UA(I)=RRAD1(I,L)*RRAD1(I,L)+ &
                      CIN*RRAD2(I,L)*RRAD2(I,L)
where RRAD1 is the first column, RRAD2 is the second column and CIN is 
specified as:
   CIN=1.d0/137.0359895d0**2
   IF (.NOT.REL) CIN=4.0*1.0D-22

Best,
Sylwia


W dniu 16.02.2023 14:33, pluto via Wien napisał(a):
> Dear Prof. Blaha,
> 
> I looked the case.radwf file. For my test case of bulk-fcc-Al it
> consists to following header:
> 
>    1 781   0.0001000000   0.0129828604   2.5000000000
> 
> Here "1" seems to indicate the atom number from the case.struct (there
> is only one inequivalent for fcc Al) and "781" indicates the number of
> mesh points between the center of the atom and the radius of the
> sphere (starting at the radius and ending at the center). Radius in
> this case is 2.5 Bohr, as also indicated.
> 
> After this there are sections, each with 781 rows. These sections are
> marked by 0, 1, 2, 3...8 which for me seems to be s, p, d, f, ...
> 
> Now each of these sections contains up to 10 columns. Can you explain
> the meaning of these columns?
> 
> To me it looks as if 2 columns are assigned to each of u, u-dot, u_lo,
> ... But I would expect a single column of real numbers, in the spirit
> of R_nl for the hydrogen.
> 
> I plotted some of these columns for check, and the first columns of
> the first section looks like 3s, but the second column looks a bit
> strange.
> 
> Best,
> Lukasz
> 
> 
> 
> 
> 
> 
> 
> 
> 
> On 2023-02-13 10:21, Peter Blaha wrote:
>> It was mentioned several times on the mailing list that
>> 
>> x lapw2 -alm
>> 
>> prints the radial functions into a file (just once) as well as all
>> Alm,Blm,... for each k-point and band-index.
>> 
>> For further details search the mailing list.
>> 
>> For the interstitial matrix elements you can get them by the integral
>> between two plane wave expansions (times the dipole operator ?)
>> multiplied with the "step-function". Such detaisl are well explained
>> in D. Singh's book...
>> 
>> 
>> Am 12.02.2023 um 20:10 schrieb pluto via Wien:
>>> Dear Prof. Blaha,
>>> 
>>> Thank you for your comments.
>>> 
>>> Are the functions u and u-dot provided in some output file? Manual 
>>> mentions different types of u and u-dot for the cases of Psi^LO and 
>>> Psi^lo. Manual also mentions that u and u-dot are obtained by 
>>> numerical integration of radial Schrodinger equation on the mesh. Are 
>>> they all tabulated somewhere?
>>> 
>>> Having all the A_lm, B_lm, C_lm and all the u and u-dot would allow 
>>> to have the full wave function Psi(r) inside the spheres as a 
>>> function of wave-vector and energy. That would allow to numerically 
>>> calculate the matrix elements which I need, with the assumption of my 
>>> favorite final state, and without any further assumptions. The only 
>>> remaining problem would be the interstitial region, but it would also 
>>> be under control by knowing how much charge leaks out of the spheres.
>>> 
>>> Best,
>>> Lukasz
>>> 
>>> 
>>> 
>>> 
>>> On 2023-02-09 18:06, Peter Blaha wrote:
>>>> 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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