[Wien] equivalent-core approximation

Thu Feb 24 14:55:29 CET 2005

Hello Michael,

I've never done Z+1 with excitation (and am not subscripted to the journal mentioned).  I've done neutral Z+1 but abandoned that, since it's as much work (computationally) as a normal core hole, and physically less nice (you would use the same core hole potential for all edges of a given atom).

An advantage of Z+1 could be that one calculation gives you information about both the original material (eels) and the doped material (other properties ...).

I don't remember having difficulties with the calculations I did (Z+1), but it's quite some time ago, and probably well-behaved C K-edges.

Perhaps someone else can add more comments.

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 Michael Gurnett
Verzonden: do 24-2-2005 13:30
Aan: wien at zeus.theochem.tuwien.ac.at
Onderwerp: Re: [Wien] equivalent-core approximation

Hi Kevin,

I have seen these and in none of them do they use the Z+1 method (substitute
a given atom for an atom to the right in the periodic table). I have been
informed that at least in the case of metals this works very well for final
state effect  surface core level shifts of valence electrons (valence
electrons cannot distinguish between an extra proton and a core hole).
However as I pointed out in the first mail, there seems to be two techniques
(one with a neutral Z+1 atom and one that is ionized).

Now I have noticed that simply changing a given atom to Z+1 is very unstable
(l2main QTL-B ERROR). So for this reason I am now trying PRATT. I am open to
other techniques that allow to simulate final state effects on core-levels
for Ge 3d electrons (approx. -1.5 ryd). So far I have tried manually placing
these in core and reducing the number of valence electrons. However, this
too was unstable. Another method I have heard about is simply using the
Slater transition state (which was found to work really well in the case of
Si 2p) on deeper core-electrons as the surface core-level shift should be
failry similar (say using 3p). This again was good for metals, and it is not
certain how well this would work for a semiconductor.

So basically any technique in which I can obtain final state effect shifts
for Ge 3d electrons is welcome

Michael

----- Original Message -----
From: "Jorissen Kevin" <Kevin.Jorissen at ua.ac.be>
To: <wien at zeus.theochem.tuwien.ac.at>
Sent: Thursday, February 24, 2005 12:30 PM
Subject: RE: [Wien] equivalent-core approximation

try new digest, january 2005, threads :
* EELS of L3 Ti edge
* calculation of core-hole spectra

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 Michael Gurnett
Verzonden: do 24-2-2005 8:10
Aan: wien at zeus.theochem.tuwien.ac.at
Onderwerp: Re: [Wien] equivalent-core approximation

Sorry, but before I wrote the email I searched the mail archive for Z+1, ECA
and equivalent core approximation without finding anything, with the
exception of Peter's email in which he discusses Slater, Delta SCF and Z+1.
Nowhere did I find any answers that I was looking for in the mailing list.
If I have missed something please let me know.

Michael

----- Original Message -----
From: "Jorissen Kevin" <Kevin.Jorissen at ua.ac.be>
To: <wien at zeus.theochem.tuwien.ac.at>
Sent: Wednesday, February 23, 2005 11:44 PM
Subject: RE: [Wien] equivalent-core approximation

Now you are being lazy ;-).
We had many e-mails about this only a month or so ago.
Please check the archive, and come back with further questions if necessary.

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 Michael Gurnett
Verzonden: wo 23-2-2005 23:17
Aan: wien at zeus.theochem.tuwien.ac.at
Onderwerp: [Wien] equivalent-core approximation

I was reading the article

"Equivalent-core calculation of core-level relaxation energies in
photoelectron spectroscopy: A molecular-orbital approach
JOURNAL OF CHEMICAL PHYSICS VOLUME 109, NUMBER 16 22 OCTOBER 1998

in which they use both the Z+1 neutral atom and also a Z+1 ionised atom to
simulate the core-hole. Has anyone used either of these techniques with the
Wien2k code. If so, which method is better, and what are the correct
procedures to perform such calculations.

Thank you

----------------------------------------------------------------
Michael Gurnett
Dept. of Physics,
Inst. of Engineering Sciences, Physics and Mathematics,
Karlstad University,
S-651 88 Karlstad, SWEDEN
Tel. +46 54 700 2175, Fax. +46 54 700 1829,
Mobile phone +46 70 590 6495
E-mail: michael.gurnett at kau.se, WWW: http://www.ingvet.kau.se/fys/
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