WAVELET TRANSFORM OF XAFS SPECTRA

MUÑOZ Manuel - FARGES François - ARGOUL Pierre

Université de Marne la Vallée - CNRS FRE 2455 - Ecole Nationale Supérieure des Ponts et Chaussées
(Polytechnicum de Marne la Vallée, France)

 

FAQ
Help
References
Source code/compatibility
Contact

 

FAQ (foire aux questions) :
   
A new approach of EXAFS spectra analysis was developped: the Continuous Cauchy Wavelet Transform (CCWT). The method provides an accurate "time-frequency" decomposition of the analyzed signal. Applied to EXAFS spectroscopy, the signal is decomposed both, in the wavevector (k) and in the distance (uncorrected for phase-shifts; R') dimensions :



Qualitative interpretations of the EXAFS spectra are directly based on the CCWT modulus, and may help, among others, next-nearest neighbors identification.

 

 

References:
Details concerning the numerical description of CCWT and illustrations of the method applied to EXAFS spectra are provided in two papers :

• Muñoz M., Argoul P. and Farges F. (2003) Continuous Cauchy wavelet transform analyses of EXAFS spectra: a qualitative approach. American Mineralogist vol. 88, pp. 694-700 [pdf]

• Muñoz M., Farges F.and Argoul P. (2003) Continuous Cauchy wavelet transform analyses of XANES and EXAFS spectra. Physica Scripta (proceeding #5220 of the XAFS-12 meeting, Malmö-Lund, Sweden, in press) [pdf]

 

 

Source code:
The Matlab/Octave script file can be freely downloaded for free here.

The script was positively tested on Matlab 5.2/MacOS9, Matlab 5.3/Win2k and Matlab 6.5/MacOSX (under both X11 or OroborOSX).

Clever non-Matlab users: OCTAVE (under the terms of the GNU General Public License ( GPL ) as published by the Free Software Foundation) is your free alternative to run this script (+ gnuplot).

 

The computed *.mat files can be reloaded in plot mode (mode = 2) to save CPU time.

Altough binaries, *.mat files are cross-platform compatible (tested Win2K —> MacOSX and MacOS9 —> MacOSX).

 

 

Contact :
Any question, remark or suggestion ? contact us at nospam@univ-mlv.fr (BUT replace "nospam" by either "munoz" OR "farges" ; this is done to short-cut scanners for spam mail - sorry for this !).