On Monday 30 August 2010 09:27:09 am sumitk@barc.gov.in wrote:
Hi all, I am doing an EXAFS spectra analysis of Eu(III) sorbed on mineral oxides. In course of this, I came across a lierature article(Geochimica et cosmochimica Acta 64(16),2737,2000.) where a residual spectra (denoting a particular shell) was generated after subtracting four other different paths contribution from the EXAFS spectra(k3.chi(k)). This procedure was adopted to identify and isolate different paths/shells informations available in the EXAFS spectra. As the paper doesnot explain about the procedure, I am little confused whether the author has adopted just the linear subtraction methodology(i.e, sum of few selected paths minus the original spectra) in creating the residual spectra or some other mathematical approach.
The caption to figure 5 in the article you cite says: "Residual EXAFS (produced by subtraction of U=Oax, U-Oeq, U-C, and U-U shells) ..." Seems pretty clear to me that what they show is the Fourier transform of data_chi(k) - sum_of_specified_paths(k) B
Any one having experience in this analysis will please repond to my problem. I would also like to know the best way to identify different shells contribution in the EXAFs spectra. Thanking in advance Sumit Kumar
-- Bruce Ravel ------------------------------------ bravel@bnl.gov National Institute of Standards and Technology Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2 Building 535A Upton NY, 11973 My homepage: http://xafs.org/BruceRavel EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/