Yanyun, Kug-Seung, Have you watched the videos that the folks at Diamond kindly host at http://www.diamond.ac.uk/Beamlines/Spectroscopy/Techniques/XAS.html The ones titled "Introduction to Artemis and EXAFS fitting" and "More Artemis and EXAFS fitting" go a long way towards answering the questions you both are asking. Granted, you have to look at my ugly face for a long time, which is pretty horrifying. But I think you might find them helpful. B -- Bruce Ravel ------------------------------------ bravel@bnl.gov National Institute of Standards and Technology Synchrotron Science Group at NSLS --- Beamlines U7A, X24A, X23A2 Building 535A Upton NY, 11973 Homepage: http://bruceravel.github.io/home/ Software: https://github.com/bruceravel Demeter: http://bruceravel.github.io/demeter/