[Ifeffit] Platinum Rhenium EXAFS in Artemis
Ravel, Bruce D.
bravel at anl.gov
Mon Apr 16 09:01:10 CDT 2007
On Sunday 15 April 2007 12:40, Edward L. Kunkes wrote:
> Hi everyone,
> I am new to EXAFS and have been working with Athena to process my data and
> trying to fit it with Artemis. I have LIII edge EXAFS data from
> monometallic carbon supported Pt, Re and bi-metallic PtRe nanoparticles
> (1-3nm). My objective to perform a first coordination shell fit, and i have
> been successful with the monometallic data and reference samples (Pt and Re
> foils and salts). Unfortunately success with PtRe bimetallics has been
> limited so far, and I can not get a good fit with reasonable delEo values.
> Did anyone work with platinum/rhenium before and can offer some helpful
> advice? The literature says that even though the backscattering properties
> of Pt and Re are similar (given their proximity on the periodic table),
> they should still be distinguishable with k0-weighted fitting.
I don't personally have experience with a system quite like that. I did spend
a fruitless couple of months a few years back trying to get something useful
out of an Fe/Ga alloy with little success.
The issue of their proximity is serious, but you can throw the whole bag of
Ifeffit tricks at the problem. Use k-weights. Use multiple data set fits
and data from both edges. Use temperature to help break the correlations
between sigma^2 and amplitude. Use clever math expressions. It doesn't seem
undoable to me.
> I was also
> if its possible to use Athena or Artemis to extract the back-scattering
> properties of Pt and Re from reference samples, and use these properties in
> fitting a Pt-Re path.
This has been on my list of things to do for a long time. See
and scroll to the end of the page. That said, I would need to be convinced
that doing so is preferable to using Feff for EXAFS analysis (with the
exception of a scattering geometry that involves an intervening hydrogen
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