[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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