Hi Yu-Chuan, Autobk uses a linear fit to the pre-edge region, and subtracts that line from the full spectra. More details are at http://cars9.uchicago.edu/autobk/ProgramDoc/node14.html Ifeffit's spline() command and Athena do the same thing. The range of the pre-edge used for the linear fit can be adjusted. Athena allows you to view the pre-edge line very easily. --Matt On Tue, 11 Jan 2005 hsnuboy@ksu.edu wrote:

Dear Ifeffit list,

There is one question I don't understand very well. How does AUTOBK algorithm handle the pre-edge background removal? I check the mannual of using ATHENA and the paper, "Near-edge x-ray-absorption fine strructure of Pb: A comparison of theory and experiment", M. Newville, et al., Phys. Rev., B47:21 (1993), 14126. Both of them have no information about dealing pre-edge background removal with AutoBK and how is it work within Athena? Hence, I ask this qustion for all the experts on the list. Thank you for your help.

Sincerely,

Yu-Chuan Lin Research Assistant Dept. of Chemical Engineering Kansas State University _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit