[Ifeffit] something is wrong with Ruthenium-Oxygen bond amplitudes

[María Elena Montero Cabrera]

Hi Scott!
Thanks a lot for your interest. The physical form was powder, and they were
measured by transmission and fluorescence. We have tried firstly the fitting
of fluorescence spectra, but we have obtained that low amplitude values. So
I have though we have autoabsorption, and decided to do the fitting of
transmission spectra. They are not exactly the same, close to the edge
fluorescence spectra have lower mu(E). I remember that Sam Webb told me that
the K edge jump was good in the absorption spectra, after calculating the
thickness with Hephaestus.  In that fitting we have obtained the same
"wrong" values. Then we decided to do the fitting of RuO2, and we have
obtained again the low amplitudes. Now I don't know what to do.
Regards
   Maria Elena


2010/11/5 Scott Calvin <dr.scott.calvin at gmail.com>

> Hi Maria,
>
> What was the physical form of the samples (powder, thin film, etc.) and how
> were they measured (transmission, fluorescence, ...)? Sometimes this kind of
> thing can stem from sample/beamline/data effects.
>
> --Scott Calvin
> Sarah Lawrence College
>
>
> On Nov 5, 2010, at 5:50 PM, María Elena Montero Cabrera wrote:
>
>  Hello friends,
>>
>> Hopping someone could help us. We are having some problems in fitting Ru
>> K-edge in a Ruthenium-cuprate sample on Artemis, with path functions
>> obtained using FEFF 8.4, where we got amplitude values of less than 0.50 for
>> Ru-O first shells. We think this value probably is wrong, although there are
>> some publications where some oxygen deficiency is studied and recorded as
>> true. The ATOMS input data was found to be ok due to the Rietveld analysis
>> results told us these are good. The reason we think we may be wrong with
>> something during the fitting appeared  because we tried to fit our reference
>> sample of RuO2 (measured under same conditions as the experiment of Ru-Cu at
>> SSRL) and we came to the same results, even worst, of amplitude lower than
>> 0.40. We are attaching the Artemis files so you can take a look on it and
>> give us some light to continue with our analysis.
>> Thanking in advance, take care
>>
>
>
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-- 
María Elena

Dra. María Elena Montero Cabrera
Centro de Investigación en Materiales Avanzados (CIMAV)
Miguel de Cervantes 120, Compl. Ind. Chihuahua
Chihuahua CP 31109, Chih. México
Tel (614) 4391123
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