[Ifeffit] inquire for the EXAFS of the mixture of species

[Carmelo Prestipino]

Hi
Here an another routine for itfa (PCA_GUI executable).
http://code.google.com/p/prestopronto/
You can use athena to create the input file (a file with one energy
column and the rest of column are spectra).
All  the best
Carmelo

>
> Message: 1
> Date: Thu, 08 Mar 2012 17:00:15 +0900
> From: Takahide Yamaguchi <11nm023s at mcs.ibaraki.ac.jp>
> To: ifeffit at millenia.cars.aps.anl.gov
> Subject: [Ifeffit] what is the reasonable arc-tan for edge jump
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> Message: 2
> Date: Thu, 8 Mar 2012 08:13:08 +0000
> From: <fred.mosselmans at diamond.ac.uk>
> To: <ifeffit at millenia.cars.aps.anl.gov>
> Subject: Re: [Ifeffit] inquire for the EXAFS of the mixture of species
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>        <CF65047C5B0562499EAFF9FBBC542D6426591B88 at EXCHMBX01.fed.cclrc.ac.uk>
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>
> Hi Winejia,
>
> I think your problem may well be harder than an LC approach as suggest by Darius will solve, as it is possible (probable) that the reaction intermediates are not known structurally so you don't have model spectrum of them. Complex solution equilibrium mixtures are about as tough as it gets for soluble EXAFS problems. The methods that tend to work are Principal component analysis (which is available in sixpack and Athena)
> This will probably tell you how many species  you have in your reactant spectra, and will also tell you by target transformation if a spectrum of a model you have is one of those species. However to identify the unknowns you may need to use a more advanced approach like iterative transformation factor analysis (ITFA) . there is an itfa package available from the RoBL esrf beamline  http://www.esrf.eu/UsersAndScience/Experiments/CRG/BM20/Software/
> This should be able to give you the spectra of the separate solution spectra which then you can analyse with Artemis.
>
> The key things you need to have is  more spectra representing in different ratios of the solution species than the total no of solution species, otherwise your problem is underdetermined, preferably quite a lot more.
>
> Regards
> Fred
>
> Prof.  J F W Mosselmans
> Principal Beamline Scientist I18
> Diamond Light Source
> Diamond House
> Harwell Campus
> Didcot
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-- 
Carmelo Prestipino
Sciences Chimiques de Rennes UMR 6226
Solid State and Materials Chemistry group (CSM)
Campus de Beaulieu, Bât 10B, bureau 122
F-35042 RENNES
France
Tel: (+33) 22323 6531
FAX: (+33) 22323 5959