[Ifeffit] Interpreting old XANES data with missing standards

[Ritimukta Sarangi]

Hi  Don,
I am sure you are aware but I would like to remind you that the sulfides that you are working with have serious potential for self absorption. Most spectra out there have different degrees of self absorption which can really mess up LCA type analysis. This is not a quick solution, but you might consider remeasuring the standards following  a strict protocol of sample dilution, grinding and deposition on substrate to minimize any such artifacts.
Best,
Riti Sarangi


Sent from my iPhone

> On Jun 8, 2018, at 7:45 AM, Carlo Segre <segre at iit.edu> wrote:
> 
> 
> You might also ask the beamline scientist at APS Sector 9, Tianpin Wu <twu at anl.gov>
> 
> carlo
> 
>> On Fri, 8 Jun 2018, Anatoly Frenkel wrote:
>> 
>> Don,
>> 
>> I am sure that Paul Northrup (northrup at bnl.gov) will help - he was the
>> beamline scientist at X15B and is likely to have the standards you need.
>> 
>> Anatoly
>> 
>> 
>> -------------------------------------------------------------------
>> 
>>> On Fri, Jun 8, 2018 at 9:54 AM, Don Baker <don.baker at mcgill.ca> wrote:
>>> 
>>> Hello All,
>>> 
>>> First let me apologize if the question below is inappropriate for this
>>> group, but I don't know of a better set of experts that I can ask.
>>> 
>>> So, here is some background:
>>> 
>>> I have some old S K-edge XANES data from NSLS X15B for S-bearing
>>> silicate glasses that was collected by a Ph.D. student who decided to
>>> leave for a good job rather than finishing their degree.  During my
>>> current sabbatical year I have been looking at the data and reading
>>> papers on the topic.  I think that I now understand, at least
>>> qualitatively, the changes in the spectra as a function of iron
>>> concentration in the glasses, but to perform quantitative modelling I
>>> need XANES spectra of MgS and CaS, which we did not think to collect all
>>> those years ago.  I have searched for XANES spectra of MgS and CaS on
>>> the CARS XAFS Data Library and on the XAFS Database at IIT without
>>> success.  I am unaware of other databases available.
>>> 
>>> Now for for my questions:
>>> 
>>> 1.  Does anyone know of a XANES database that contains MgS and CaS
>>> spectra?  (Or did I miss it in the databases I searched?)
>>> 
>>> 2.  If I cannot find measured MgS and CaS spectra, what do you think
>>> about using calculated spectra (e.g., Zheng et al.,2012, NPJ
>>> Computational Materials, 12 -- which uses FEFF) for quantitative
>>> modelling?
>>> 
>>> 
>>> And information, ideas, and suggestions that you may have will be
>>> appreciated.
>>> 
>>> 
>>> Wishing you all the best from a spring morning in Montreal,
>>> 
>>> Don
>>> 
>>> 
>>> 
>>> 
>>> --
>>> Melting rocks today for a better tomorrow . . .
>>> Don R. Baker, Professor of Geochemistry, Earth and Planetary Sciences,
>>> McGill University
>>> 
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>> 
> 
> -- 
> 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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