[Ifeffit] lifetime broadening of pre-edge peaks?

[Anatoly I Frenkel]

I think experimental answer could be the simplest one. Perhaps there is anyone on the list who measured low concentrations of low Z absorber in the high Z host at both edges?

For example, Cu in Ag (if does dissolve in Ag if made by rapid quenching) at Cu K-edge, and Ag K-edge (or just bulk Ag since the data will be the same). These should be solid solutions, of course.



Then, despite the difference in phase shift, the EXAFS oscillations should be comparable in magnitude if the broadening is not significant, and it should be more intense for the Cu K-edge if the broadening at Ag K edge is significant.



Another option: to hear from people doing HERFD. That is normally done on XANES, for the reason,  I assume, that they do not see any advantage in EXAFS region, where broadening does not change compared to total fluorescence.



I think the explanation that EXAFS should not be too sensitive to the life time broadening is that EXAFS originates from the final state interference, while the XANES - from both the final state interference and DOS. But may be experiments are showing the opposite, and that will prove me wrong.



Anatoly

________________________________
From: ifeffit-bounces at millenia.cars.aps.anl.gov [ifeffit-bounces at millenia.cars.aps.anl.gov] on behalf of Matthew Marcus [mamarcus at lbl.gov]
Sent: Monday, October 10, 2011 2:23 PM
To: XAFS Analysis using Ifeffit
Subject: Re: [Ifeffit] lifetime broadening of pre-edge peaks?

Thanks.  While none of these have to do with pre-edge peaks such as are found in transition-metal oxides, the assumption of constancy of core-hole broadening does seem to work.
    mam
----- Original Message -----
From: Iztok Arčon<mailto:iztok.arcon at ung.si>
To: XAFS Analysis using Ifeffit<mailto:ifeffit at millenia.cars.aps.anl.gov>
Sent: Monday, October 10, 2011 12:32 AM
Subject: Re: [Ifeffit] lifetime broadening of pre-edge peaks?

Dear Matthew

you can find examples of determination of life-time broadening, deconvolution of XANES specra, and discussion about limitations due to noise in several papers, for example:

A. Filipponi, J. Phys. B 33, 2835 (2000)

A. Kodre, I. Arčon, J. Padeznik Gomilšek, R. Frahm
J. Phys. B: At. Mol. Opt. Phys. 35 (2002) 3497-3513

A. Kodre, J. Padežnik Gomilšek, A. Mihelič, I. Arcon
Radiation Physics and  Chemistry 75 (2006) 188-194

J. Padeznik Gomilsek, I. Arcon, S. de Panfilis, A. Kodre,
Phys. Rev. A 79,  (2009) 032514,

regards
Iztok

Matthew Marcus wrote:
Is the core-hole lifetime broadening of pre-edge XANES peaks the same as at the main edge?  I'm looking into issues of de-noising of XANES epsctra, so
need to figure out how narrow real features can be.
    mam
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--
prof. dr. Iztok Arcon
University of Nova Gorica
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