[Wien] Final state effects in photoemission

[Lukasz Plucinski]

> yes. Using Slater transition states. remove half an electron from the atom
> in question. Then add this half electron back in mixer. Do a search in the
> older messages for slater transition and you should find what your looking
> for
>
> Mick

Dear Mick and All Users,

I checked archives and found a message posted by Prof. Blaha (see below).
I also found paper by D.A. Liberman PRB 62, 6851 (2000) about Slater
transition-states.

I need to make calculations for GaN - its about a 3d satellite at 3p
threshold (hv about 105 eV) in resonant photoemission. As written in Iwan
et al. about Cu and Ni, PRL 43, 1829 (1979), these states can be
described by a 'quasiatomic shakeup state involving two correlated 3d
holes plus a low lying excited nl electron...'

Do you think I can simulate such states with WIEN2k by removing electrons
from Ga 3d states?

I will keep learning on this subject, I have, however, 2 basic questions:

1. Why should I remove just 1/2 electron from the core state? Is that a
simple intuitive explanation?

2. In photoemission not so many atoms are ionized at the same time. How
the results with half electron per unit cell removed could be related to
reality? I would think its necessary to use large supercell and ionize
just one of the atoms by removing 1 electron (like it happens in
photoemission) - probably supercell should be so large that the
ionized atoms from the adjacent supercells do not interact - am I right?
(I guess Prof. Blaha meant the same at the end of his old e-mail - see
below).

Please help or give a hint!

Regards,

Lukasz


Date: Fri, 28 Sep 2001 08:46:37 +0200 (MEST) From: Peter Blaha
<pblaha at theochem.tuwien.ac.at> Subject: Re: [WIEN]: Slater's transition
state ==== Peter Blaha <pblaha at theochem.tuwien.ac.at> submitted the
following contribution: ====
> 	In one of the old messages (last year) from the WIEN mailing list
> it was mentioned that Slater's transition state were possible with
version
> WIEN97.10 :
> We would like to calculate such quantity for silicon (2p core level).
How
> should I proceed ? Do I modify <case>.inst by specifying explicitely the
> occupation to be 1/2 for some levels :
After a complete initialization (and also scf calculation with save_lapw)
you should edit case.inc and reduce the occupation of a Si 2p state by
0.5.
> And/Or, do I modify the extra charge in <case>.inm to some value (0.5
?):
>
> BROYD  0.0   YES  (BROYD/PRATT, extra charge (+1 for additional e),
norm)
> 0.40 FACTOR
Yes, you also should either put -0.5 into case.inm, or equivalently (?)
increase the number of valence electrons (NE in case.in2) by 0.5 (In some
spectroscopies you excite the core electron to unoccupied states and do
not ionize the atom). In any case, check if NEC01 is what you expect and
does not give a wrong renormalization. No other changes are required.
However, in principle, an even better result can be obtained by creating a
supercell und putting the corehole in just one out of several Si atoms.
(E.g. going to P lattice with 8 Si atoms). Regards
                                     P.Blaha