On Friday, January 04, 2013 05:48:24 PM Zhaomo Tian wrote:
I try to analyze EXAFS data(Cu k-edge was probed) of bare Cu thin film and Cu thin film with CO gas adsorption. However, before the fitting, I found that the first main peak of bare Cu thin film appears at R around 2.2 angstrom, but the nearest neighbor distance of Cu is actually at R around 2.5 angstrom, are there something wrong with my data or is it a normal phenomenon? And when I tried phase correction in Athena or used FEFF calculated 1st path for phase correction in Artemis, the peak became closed to R=2.5 angstrom, which seemed more reasonable. But I guess phase correction is not a necessary process, then what should I do to make the 1st main peak position consistent with the right value?
Zhaomo, I tend to agree with Chris. You seem to be asking questions that are answered in great detail and by many people in places that are easily found on the web. You should spend some quelity time following the links at http://www.xafs.org/Tutorials A google search of "exafs phase shift" turned up plenty of useful links right on the first page, including this discussion from 2004 from this very mailing list: http://millenia.cars.aps.anl.gov/pipermail/ifeffit/2004-July/005768.html 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 Homepage: http://xafs.org/BruceRavel Software: https://github.com/bruceravel