[Ifeffit] Re : EXAFS analysis of a sample having two metal centres with different coordination geometry

[Abhijeet Gaur]

<Abhijeet,

<This seems like a system which might require more information before using
EXAFS analysis.  How did you come to the conclusion that there are
<two metal centers?  You begin by asking how to model two metal centers with
different coordination and then in question 3, you lead the list to
<believe that there might not be two metal centers?  I assume you have found
structural data for the sample?  You have different geometry as
<well as different ligands (atoms).  Do the metal centers only contain the
absorbing metal or is it mixed?  If you had a bit more information
<about the material through other methods, I am sure several people could
suggest helpful ideas for your analysis.

<Chris

-- 
Christopher J. Patridge PhD.
405 NSC - Dept of Chemistry
University at Buffalo
State University of New York
Buffalo, NY 14260
Office:(716)645-4137
Contact:(315)529-0501
<E-mail: patridge at
buffalo.edu<http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit>

Dear Chris,
               I am sorry for making my problem a bit difficult to
understand. Let me clarify the problem:
1. Yes, I have the crystal strcuture of the sample with me, from which I
know that there are two metal centers. With this crystal strcuture data, I
have generated the theoretical model for the two metal sites.
2. Yes, the metal centers only contain the absorbing metal, i.e., copper but
with with different coordination.

    And my question is whether by using EXAFS analysis of experimetal data,
the contribution of two metal center present in sample can be confirmed?
    Also, is it possible to calculate that how much one metal center
contribute to the experimetal data?
    If, one of the theoretical model does not fit to the experimetal EXAFS
data, what does it signify about the corresponding metal center?

  I hope this will make my problem clear to the members of the mailing list.

With thanks
Abhijeet Gaur
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