[Ifeffit] problems

Matt Newville newville at cars.uchicago.edu
Fri Jul 13 22:20:41 CDT 2012


On Fri, Jul 13, 2012 at 5:21 PM, johnny huertas <johnnyhf at hotmail.com> wrote:
> Members of list:
> I have some problems to resolve a question. I have been working a lot in fit
> the AgBr(1-x)Clx example of FEFFIT site. My fits were good in my  opinion,
> but I don't know how to identify the Br and Cl atomic distribution around Ag
> (random or specific?). I didn't find any example about this in the site.
> Conversely I have made some attempts to identify such distribution. I have
> made two fits preparing for each one feff file, a feff file puting Br and Cl
> atoms in face and other in medirian position around Ag knowing the CN=6 of
> this central atom and fiting only the first shell. Unfortunatelly I don't
> have found satisfactory results because the paremeter are equal in both
> cases. I would like you help showing a similar example. Thanks.

As is often requested on this list, it would be most helpful if you
asked specific questions, and possibly post a project of what you've
done and a clear explanation of what you are trying to do.  Open ended
questions are just too difficult to address.   Are you asking how to
include both Ag-Br and Ag-Cl in a fit, or asking if you can
distinguish random substitution from ordered substitution?     I'm not
sure why the Ag-Br and Ag-Cl parameters would be the same, but it's
too hard to speculate without knowing what you actually did.


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