EXAFS analysis of a sample having two metal centres with different coordination geometry
Hi all, I am doing EXAFS analysis of a sample having two metal centres with different coordination geometry. In my sample two (Cu) metal centres are present and these metal centres are surrounded by different ligands (atoms) in different coordination geometry. As I understand the EXAFS data of such sample will have contributions from both the metal centres. So, in order to analyse the EXAFS data, I have generated theoretical model (using Artemis) for both the metal centres. Then, I have fitted these theoretical models to the experimetal data. But, I have some questions regarding this type of analysis as I am not sure whether I going in right direction or not: 1. I have to fit these theoretical models one by one or simultaneously to the experimetal data. 2. How can I confirm that whether the EXAFS data of the sample has contributions from both the metal centres. 3. If one of the model does not fit well to the exp data, does this mean that the corresponding metal centre is not present or the metal centre is present but not contributing. 4. Is it possible to calculate the percentage of contributions from different metal centres to the experimetal data. If someone can suggest some available literature on this problem, it will be really helpful to me. With thanks Abhijeet Gaur Research Scholar School of Studies in Physics Vikram University, Ujjain, India
On 7/21/2011 3:44 PM, Abhijeet Gaur wrote:
Hi all, I am doing EXAFS analysis of a sample having two metal centres with different coordination geometry. In my sample two (Cu) metal centres are present and these metal centres are surrounded by different ligands (atoms) in different coordination geometry. As I understand the EXAFS data of such sample will have contributions from both the metal centres. So, in order to analyse the EXAFS data, I have generated theoretical model (using Artemis) for both the metal centres. Then, I have fitted these theoretical models to the experimetal data. But, I have some questions regarding this type of analysis as I am not sure whether I going in right direction or not: 1. I have to fit these theoretical models one by one or simultaneously to the experimetal data. 2. How can I confirm that whether the EXAFS data of the sample has contributions from both the metal centres. 3. If one of the model does not fit well to the exp data, does this mean that the corresponding metal centre is not present or the metal centre is present but not contributing. 4. Is it possible to calculate the percentage of contributions from different metal centres to the experimetal data. If someone can suggest some available literature on this problem, it will be really helpful to me. With thanks Abhijeet Gaur Research Scholar School of Studies in Physics Vikram University, Ujjain, India
_______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit 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@buffalo.edu
participants (2)
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Abhijeet Gaur -
Chris Patridge