[Ifeffit] Linear Combination Fitting using ATHENA

[Teck Kwang Choo]

Thanks Matthew for the spectra.

Is it correct to use the spectra that was taken in transmission mode (the
one you did) to fit those taken in fluorescence mode (my case)?

Teck Kwang


On 14 August 2013 01:37, Matthew Marcus <mamarcus at lbl.gov> wrote:

> Here are reference spectra.  The calibration is defined with the Fe metal
> edge at 7110.75eV.  The maghemite spectrum has been corrected for mild
> overabsorption by reference to magnetite, which is very similar.  The
> magnetite is synthetic Fe3O4 from Aldrich, and done in TEY, so no
> overabsorption.
> The maghemite is from oxidation of Fe oxide nanoparticles and has been
> verified by XRD and comparison with the ETH group's maghemite spectrum.
>         mam
>
>
> On 8/13/2013 1:33 AM, Teck Kwang Choo wrote:
>
>> Hi all,
>>
>> @Drew Latta: I was wondering why the end members should be magnetite and
>> maghemite. Is it because they are both of inverse-spinel structure, the
>> difference only being that the latter has all Fe completely oxidized into
>> Fe(III)? Would you be able to provide the standard spectra to me if that is
>> the case? Thanks very much!
>>
>> Previously I have only thought of using hematite (alpha-Fe2O3) and FeO as
>> end-members, both representing Fe(III) and Fe(II) respectively without
>> giving much thought to the structure Fe takes. I also had my doubts using
>> magnetite (Fe3O4) as a standard as it is a mixture of both Fe (II) and Fe
>> (III). But thanks to the insights Drew has given, I now think I should take
>> the Fe-coordination environment into account with the use of magnetite and
>> maghemite as standards.
>>
>> @Alexandre and Matthew: I have obtained Mossbauer spectra of some of my
>> samples but like Drew said, it is not straightforward at this point in
>> time. Will see what I can do with the data I have!
>>
>> Thanks for all your responses! It is greatly appreciated! This forum has
>> been more helpful than I thought!
>>
>> Teck Kwang
>>
>>
>> On 13 August 2013 01:34, Matthew Marcus <mamarcus at lbl.gov <mailto:
>> mamarcus at lbl.gov>> wrote:
>>
>>     While it's true that Mossbauer is the gold standard for Fe valence
>> determination, access to the technique isn't all that common, and I don't
>> know
>>     of any facility that can do it on a micro scale.  Is there one?
>>              mam
>>
>>
>>     On 8/12/2013 7:01 AM, Alexandre dos Santos Anastacio wrote:
>>
>>         Hello,
>>
>>         maybe that fingerprinting technique would be Mossbauer
>> spectroscopy. The Fe(II)/Fe(III) ratio comes easily and also there are lots
>> of papers about Mg-ferrite, an example:
>>
>>         10.1109/TMAG.2009.2018880 <http://dx.doi.org/10.1109/__**
>> TMAG.2009.2018880 <http://dx.doi.org/10.1109/__TMAG.2009.2018880> <
>> http://dx.doi.org/10.1109/**TMAG.2009.2018880<http://dx.doi.org/10.1109/TMAG.2009.2018880>
>> >>
>>
>>         Alexandre.
>>
>>
>>
>>
>>
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>>
>>
>> --
>> Teck Kwang Choo
>> PhD Student
>> Department of Chemical Engineering
>> Room 225, Building 36
>> Monash University
>> Mobile No.: 04-11489904
>>
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-- 
Teck Kwang Choo
PhD Student
Department of Chemical Engineering
Room 225, Building 36
Monash University
Mobile No.: 04-11489904
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