[Ifeffit] Fitting EXAFS simulation to experimental

Carl Brozek brozek at mit.edu
Thu May 29 11:33:46 CDT 2014

Dear All,

Thank you for your responses so far and I apologize for not being clearer.

Here is the problem at hand: I have a material that is best thought of as
organic, graphene-like 2-D sheets connected by infinite chains of Fe-S.
Based on PXRD and other techniques, we know the structure of the AB plane
(the 2-D organic part), but we aren't able to make sense of what is going
on with the Fe-S chain. We can simulate the PXRD based on proposed .cif
files, but it's off most likely because of the c direction (Fe-S chain).

We collected Fe K edge XAS to tease out Fe-S bond angles and distances,
hoping we could feed this into our simulation for the PXRD to improve the

Modifying the ATOMS input by hand, by constructing different reasonable
geometries, was improving the simulation, but using a error minimization
fitting program would be best.

So, is it possible to vary specific angles and distances between atoms
along the c-direction only in an error minimization program based on our
experimental data?

I apologize if you have already responded to this reformulated question.


On Wed, May 28, 2014 at 6:58 PM, Carl Brozek <brozek at mit.edu> wrote:

> Dear listhost,
> I'm using Artemis as a front end for ATOMS and FEFF and I would like to
> build a simulated EXAFS spectrum based on experimental data I have. I know
> how to generate a simulation based on a .cif or .xyz file, but is it
> possible to vary parameters in these input geometries to best match the
> experimental?
> Has someone implemented this in artemis or matlab?
> thanks,
> Carl
> --
> PhD Candidate | Chemistry | MIT
> SB | 2010 | University of Chicago

PhD Candidate | Chemistry | MIT
SB | 2010 | University of Chicago
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