[Ifeffit] Basic EXAFS question

Anatoly I Frenkel afrenke2 at yu.edu
Thu Jun 27 09:18:59 CDT 2013


You will see the Ge K-edge rising just before the rise of Ta L2 edge. In principle, if you collect good quality data around Ta L2 edge (that is, from ~ 150 eV below and up to 500 eV above (because Ta L3 edge will come up after that)), you may be able to isolate the Ge K-edge peak from Ta L2 pre-edge.
But, of course, it will be only the region in the immediate vicinity of Ge 1s-4p transition peak, not post-edge.
Still, you may be able to tell between oxidized and reduced Ge based on the peak shape, as they are very different between these two states.
I doubt you can do much more than that. And, of course, no EXAFS. 

For such separation you will need to approximate Ta L2 edge using a combination of arctan and Lorentzian curves (please see the literature for different methods for such fits). You will be lucky if Ta L2 pre-edge is smooth and can be fit analytically (I haven't done it and it will not work if it has any pre-edge peaks).

From: ifeffit-bounces at millenia.cars.aps.anl.gov [ifeffit-bounces at millenia.cars.aps.anl.gov] on behalf of Darren Dale [dsdale24 at gmail.com]
Sent: Thursday, June 27, 2013 9:48 AM
To: ifeffit at millenia.cars.aps.anl.gov
Subject: [Ifeffit] Basic EXAFS question

Hello All,

If I have a Ta(1-x)Ge(x)O(y) thin film, with Germanium concentration
of a few percent, is it possible in principle to get useable
fluorescence-mode EXAFS spectra around the Ge K edge (11.1 keV)? Or is
it likely that the spectra would be complicated by additional Ge
fluorescence excited by processes triggered by Tantalum L edge
absorption (9.88, 11.13, 11.68 keV)?

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