[Ifeffit] Generating single scattering paths in Artemis

Carlo U. Segre segre at iit.edu
Wed Jan 5 21:36:11 CST 2005


I think that Anatoly's posts answer this question.  The calculation of the 
overlaps requires some kind of three-dimensional environment (or the use 
of the OVERLAP card which I was not familiar with and whose documentation 
in the FEFF manual is a bit cryptic).  There are differences between a 
single neighbor at a specific distance and a coordination shell of the 
same neighbor at the same distance.

Sam's program clearly does the calculation by building a coordination 
sphere while Anatoly's method lets FEFF do it automagically.  Apparently 
the results are the same.


On Wed, 5 Jan 2005 scalvin at slc.edu wrote:

> Hi all,
> A question for Carlo--I guess I'm not clear on what the impact is of
> tetrahedral vs. octahedral or whatever if all you're doing is a
> single-scattering nearest-neighbor EXAFS analysis. Isn't a symmetric
> octahedral arrangment just the single-scattering path with a degeneracy of
> 6; a tetrahedral a degeneracy of 4; etc.? Why have FEFF calculate anything
> other than the single-scattering path?

Carlo U. Segre -- Professor of Physics
Associate Dean for Special Projects, Graduate College
Illinois Institute of Technology
Voice: 312.567.3498            Fax: 312.567.3494
Carlo.Segre at iit.edu    http://www.iit.edu/~segre

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