[Ifeffit] No shift in XANES absorption peak
segre at iit.edu
Mon Jun 11 11:35:59 CDT 2018
yes, the coordination number needs to be varied. The edges certainly do
not show a significant change.
On Mon, 11 Jun 2018, Disha Gupta wrote:
> Dear Dr Carlo
> The edges are almost identical. The pre-edge intensity change isn't that
> significant I feel. I did the Artemis fittings with the coordination
> numbers fixed. Maybe I can try varying the coordination numbers and see if
> it gives a different result.
> I have attached the images of the pre-edge and main peak.
> Thanks and Regards
> From: Carlo Segre <segre at iit.edu>
> Date: Mon, Jun 11, 2018, 12:34
> Subject: Re: [Ifeffit] No shift in XANES absorption peak
> To: XAFS Analysis using Ifeffit <ifeffit at millenia.cars.aps.anl.gov>
> Hi Disha:
> it would be good to see the XANES you are referring to. Are the edges
> identical or do they change but not shift significantly? Is the
> coordination number also constant? Generally, the bond distance will
> change with oxidation state if the coordination number is constant but if
> the coordination number changes, then there could be a change in bond
> length too.
> On Mon, 11 Jun 2018, Disha Gupta wrote:
>> Dear All
>> Firstly, I would like to say sorry if I have missed out on this discussion
>> before but it would be great if you could help me out.
>> I have been analyzing some Mn K-edge XAS data for some battery materials.
>> While the XANES data shows no shift in the main absorption peak which
>> that there is no oxidation change happening, however, when I am fitting
>> data in Artemis, I can see a shift in the bond lengths suggesting an
>> oxidation change. Is it possible that bond lengths change even though
>> spectra show no change?
>> Thank you and Kind Regards
Carlo U. Segre -- Duchossois Leadership Professor of Physics
Interim Chair, Department of Chemistry
Director, Center for Synchrotron Radiation Research and Instrumentation
Illinois Institute of Technology
Voice: 312.567.3498 Fax: 312.567.3494
segre at iit.edu http://phys.iit.edu/~segre segre at debian.org
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