On Tuesday 25 August 2009 11:02:26 am Chris Patridge wrote:
Hello all,
After calibration, alignment and merging V K edge data, there seems to be a large peak in R space below 1 A. From most examples and readings, this would seem to be noise since atoms do not reside that close to each other. Adding a background addresses this noise but then the number of variables becomes too large and meaningless to the first shell R space range. I believe the problem lies with the large pre edge feature seen with high valence state Vanadium compounds. Any suggestions on how to work through this and make realistic EXAFS analysis on these compounds.
Thanks everyone,
Didn't Richard Mayes answer this same question from you last month? http://millenia.cars.aps.anl.gov/pipermail/ifeffit/2009-July/004365.html In my experience, Richard's answer was spot on for V K edge data. If Richard's good advice didn't help, then you need to be more explicit about what the problem is, perhaps by posting a small athena project file that demonstrates the problem. B -- 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/