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

[fred.mosselmans at diamond.ac.uk]

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
Oxon
OX11 ODE
UK





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