[Ifeffit] E0 for bulk crystals and nanoparticles

Leandro Araujo leandrolangie at gmail.com
Sun Feb 25 20:44:35 CST 2007

Hi Bruce,

thank you very much for taking the time to write your helpful reply.

As you mentioned,

> This really gets at the heart of why exafs analysis is difficult.  You
> are certainly correct that the deltaE0 is highly correlated with delR
> and C3.  That correlation is hard to avoid in a non-linear analysis
> as all three terms effect the phase of the calculated chi(k).

That's exactly why I decided to post the question on the list asking for the
advice of more experienced people who can certainly evaluate the question
much better than myself.

Also, I've always been trying to follow your "reasonable and defensible
applied to all the parameters, not just e0" motto; another strong motivation
for posting this question on the list. I don't know if it is just me, but in
my short time working with EXAFS I got the strong impression that it is very
easy to fall into the temptation of sophistry to get to the "expected"
results from a fit. In this respect, I consider the mailing list an
invaluable resource to help overcoming such a temptation.

But coming back to the original question, would you say that analyzing a
temperature-dependent set of the very same NC-containing sample (eight
measurements between 10K and 300K) to get an E0 value would be a sound
approach? Or should we expect E0 to vary with the temperature as well?

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