[Ifeffit] Re xanes feff8 sulfur

s440697 at stud.uni-goettingen.de s440697 at stud.uni-goettingen.de
Tue Oct 16 04:17:11 CDT 2007


Hi Shelly,

this is no problem with the late answer. Thanks for your hint. I will talk
about this with my boss for further proceeding.

cheers,
Eckhard


> Hi Eckard,
>
>
>
> I realize that you have posted a message every month for about 3 months
> in a row without any reply:  Shame on us... I will try to answer some of
> your questions and maybe that will help to get some discussion going.
> The energy scale in feff8 is NOT defined as you would expect it to be
> for determining the absolute energy of an edge.  The energy scale in
> FEFF8 is related to the difference between the energy level of the
> intersist (potential level inbetween the muffin tins that represent
> atoms) and the threshold energy level for the excitation of the
> electron.
>
>
>
> I realize that this doesn't solve your problem, but hopefully it will
> spark some discussion.
>
>
>
> Cheers,
>
> Shelly
>
>
>
>
> Mon Aug 13 06:00:19 CDT 2007
> Does anybody know a person, who has experience respective the topics
> xanes+feff8 and sulfur K-Edges?
> I would be very thankful for an answer :-)
>
> sincerely yours,
> Eckhard Bosman
>
>
>
>
> Tue Jul 10 10:07:38 CDT 2007
>
> Hello,
>
> i have problems with feff-xanes calculations related to pyrite. I try to
> get the k-edge of sulfur (as absorber) in FeS2. I get the edge at ~2472
> eV
> and i think this is wrong because i get the same energy with gypsum and
> i
> think there should be an energyshift related to 2472 eV. My proceeding
> is
> as follows:
>
> calculate the atomic positions with the asymetric unit from the
> http://rruff.geo.arizona.edu/AMS/amcsd.php database (Pyrite spacegroup
> Pa3) respectively
> http://rruff.geo.arizona.edu/AMS/xtal_data/CIFfiles/00596.cif
> with "powdercell 2.4"
>
> feffrun with the feff.inp-file like in the attachment
> (thanks to Josh Kas for his feff-hints)
>
> I started the feff-run on the one hand with 12 atoms (unitcell) and on
> the
> other hand with 22 atoms (14x Fe and 8x S in the cube)
>
> After this i plotted from xmu.dat the absorbtion mu (column 4) as a
> function of the energy (column 1). The result is in the attachment too.
>
> I don't know why i get everytime the Sulfur-k-edge at the same position
> (for pyrite or gypsum) respectively without energyshift related to 2472
> eV.
>
> many thanks for your help :-)
> Ciao,
> Eckhard
>
>
>
> Fri Jun 15 08:48:21 CDT 2007
>
> Hallo @all,
>
> (first at all, sorry for my bad english)
>
> i'm a student working on my diploma thesis (nexafs/xanes) and my job is
> to
> simulate with FEFF 8.4 spectra, for example absorption as a function of
> energy (mu_(E)). I'm a newbie in this topic and i tried to get the
> k-edge
> of Sulfur for the substance gypsum (CaSO4 * 2(H2O)) and pyrite (FeS2).
> I'm
> interested in the XANES-range of the spectra not the EXAFS. I get
> everytime my peaks at ~2472 eV for Sulfur as absorber whatever substance
> i
> use (gypsum, pyrite,...). There are no differences with the peak
> position
> on the energy-scale or shifts. I'm really confused :-( I think, there
> should be differences in the spectra... I send you two feff.inp files
> from
> my feff-runs. My source is the mineralogy database
> (http://rruff.geo.arizona.edu/AMS/amcsd.php) where i get the data for
> the
> unitcell. Then i put the data in the XtalDraw program to get the
> positions
> of the Atoms in Angstrom, by the way i get i nice 3D-View of the
> unitcell
> :-). Then i put the values of the positions into feff...
> I simulated pyrite with 12 atoms and gypsum with 48.
> I'm appreciative for every help :-)
>
> ciao,
> Eckhard
>
>
>
> _______________________________________________
> Ifeffit mailing list
> Ifeffit at millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>


---------------------------------
Eckhard Bosman
e.bosman at stud.uni-goettingen.de
+49 (0)551-39-14441
Raum: E0.104
Institut für Röntgenphysik
Friedrich-Hund-Platz 1
37077 Göttingen
Germany




More information about the Ifeffit mailing list