[Wien] Calculation of core-hole spectra

[Jorissen Kevin]

Rebecca,
 
I think you can see it this way :
 
a 'core-hole calculation' is sometimes also called a 'final state approximation'.  The extra electron that you put into case.in2 (== lowest unoccupied state of the ground state), is more or less the electron after the transition.
The orbital that it occupies, is one that should be available for the transition.
 
Your proposed approach :
* << run_lapw >> calculates eigenstates in the final state approximation (one extra electron in case.in2)
* << x lapw2 -qtl >>> but only fills them with as many electrons as in ground state (without extra electron)
* << x telnes >> so that transitions (which are calculated only for states above the Fermi level, so unoccupied states) will include that to the lowest unoccupied state where you'd initially put an excited (final state) electron.
 
If you use the background charge (.inm), you don't have to bother about all that, of course.
 
 
Kevin Jorissen
 
EMAT - Electron Microscopy for Materials Science   (http://webhost.ua.ac.be/emat/)
Dept. of Physics
 
UA - Universiteit Antwerpen
Groenenborgerlaan 171
B-2020 Antwerpen
Belgium
 
tel  +32 3 2653249
fax + 32 3 2653257
e-mail kevin.jorissen at ua.ac.be
 

________________________________

Van: wien-admin at zeus.theochem.tuwien.ac.at namens Rebecca Nicholls
Verzonden: vr 14-1-2005 13:05
Aan: wien at zeus.theochem.tuwien.ac.at
Onderwerp: RE: [Wien] Calculation of core-hole spectra




Oh I see.
So I can either simulate the structure with a forced excitation, in
which case I take an electron from the core (.inc) and add it into
the valence (.in2) or I calculate the structure with a core elctron
missing in which case I smear it over the whole unit cell (.inm)

Thank you kevin : )

So then for Peter's comment:

> > run_lapw
> > edit case.in2 and set the number of electrons back to "normal"
> > run you spectra.

just apply then if I am adding my electron into the valence,and I
do this before I calculate the partial charges?
Is that correct?

best wishes
Rebecca


In message <6DB413F24C4D384A9A48E92CF7299EE11D100F at xmail01.ad.ua.ac.be>
wien at zeus.theochem.tuwien.ac.at writes:
> Dear Rebecca,
> 
> Only one electron is moved, that is : taken out of the core orbital (case.inc)
and going either to the first unoccupied state (== the edge onset) as a valence
electron (you 'explicitly do the excitation'; add 1 valence electron in
case.in2) or smeared out across the unit cell as a uniform charge (which means
it is not considered in any way; add a background charge in case.inm).
> 
> 
> 
> Kevin Jorissen
> 
> EMAT - Electron Microscopy for Materials Science   (http://webhost.ua.ac.be/emat/)
> Dept. of Physics
> 
> UA - Universiteit Antwerpen
> Groenenborgerlaan 171
> B-2020 Antwerpen
> Belgium
> 
> tel  +32 3 2653249
> fax + 32 3 2653257
> e-mail kevin.jorissen at ua.ac.be
> 
>
> ________________________________
>
> Van: wien-admin at zeus.theochem.tuwien.ac.at namens Rebecca Nicholls
> Verzonden: do 13-1-2005 17:32
> Aan: wien at zeus.theochem.tuwien.ac.at
> Onderwerp: [Wien] Calculation of core-hole spectra
>
>
>
>
> hello everyone
>
> I would just like to check that the method I am going to use
> for calculating core-hole EEL spectra involves adding and removing
> electrons at the right time:
>
> create supercell
> remove electron from .inc and .in2
> add electron into .inm
> run scf cycle
> add electron in .in2
> x lapw2 -qtl
> x initelnes
> x tetra
> x telnes
>
> all comments appreciated!
>
> thank you
> Rebecca
>
>
> > EELS (and X-ray absorption) spectra have a core-hole as final state. In
> > most cases this should NOT be neclected!
> > You can simulate it with WIEN by creation of a small supercell and put
> > a core hole on one of your atoms, promoting this electron into valence.
> > /edit case.inc and reduce the core oppupation; edit case.in2 and add this
> > electron.
> > run_lapw
> > edit case.in2 and set the number of electrons back to "normal"
> > run you spectra.
>
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>

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