On Wednesday 13 December 2006 22:19, Mehdi Ali wrote:
I have a question what does Rbkg option in athena does. What is its physical significance. I am new to exaf data analysis.
There is a ton of information about exafs analysis at http://xafs.org. In particular, check out the Tutorials section. The meaning of Rbkg is covered with pretty pictures in the first of Shelly Kelly's tutorials around page 30. In short (and I recommend you look at the figure on page 30 of Shelly's presentation), Rbkg is the cutoff in Fourier space between the part of the measured spectrum that is the background and the part that is data. The oscillatory chi(k) function has frequencies that are related to inter-atomic distances. Frequencies below some value, then, are associated with the background function. The spline is adjusted such that the Fourier components below Rbkg are minimized. A typical value for Rbkg is about half the near neighbor distance. HTH B -- Bruce Ravel ---------------------------------------------- bravel@anl.gov Molecular Environmental Science Group, Building 203, Room E-165 MRCAT, Sector 10, Advanced Photon Source, Building 433, Room B007 Argonne National Laboratory phone and voice mail: (1) 630 252 5033 Argonne IL 60439, USA fax: (1) 630 252 9793 My homepage: http://cars9.uchicago.edu/~ravel EXAFS software: http://cars9.uchicago.edu/~ravel/software/