[Ifeffit] Question about shift in E0

["Dr. Dariusz A. Zając"]

Hi Brandon,
before someone gives you correct answer, could you shortly inform us, 
what is the E0 for reference foil, for each experimental data. As I 
understand you have a shift of 7eV between samples, but measured on 
samples, thus would be nice to see what is the shift for reference.
The second question comes for me automatically - have you done something 
with the beamline set-up between experiments ?
kicaj

W dniu 11-06-06 08:56, Brandon Reese pisze:
> Hi all,
>
> I am looking at EXAFS of thin film metal oxides.  I am varying both 
> metal content and the oxygen content of the films. I aligned the scans 
> with a metal reference foil collected simultaneously.  In Artemis, I 
> have noticed that when changing between films with no extra oxygen 
> versus those with extra oxygen there is a shift in the fitted E0 of 
> ~1.5 eV (after aligning to the foil). I tried setting the E0 in Athena 
> to the peak of the 1st derivative and the peak of the white line with 
> the same result (~7 eV difference). I was a little surprised by the 
> offset because in Athena the E0 values varied by <0.5 eV. I am not 
> sure if the argument could be made that this shift is a result in a 
> changing oxidation state because it doesn't show up in the XANES (at 
> least qualitatively).  Are there other experimental effects that could 
> cause a shift like this, or is this likely something real in my 
> material? If anyone want to see a representative group of data, let me 
> know.
>
> I also have an unrelated quick (I think) question on the EXAFS 
> equation. In some references I see a term 1/(k R)^2 and in others it 
> is 1/(k R^2). I couldn't really see any reason for the difference, 
> unless it is to correct for subtle differences in how the other terms 
> are defined.
>
> Thanks
> Brandon
>
>
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