Claudia, The implementation of the XANES self-absorption corrections follows the thing that Daniel Haskel wrote up here: http://www.aps.anl.gov/xfd/people/haskel/fluo.html The algorithm used is explained on pages 5-9 of the postscript file on that web page. The angles are defined relative to the surface, not the surface normal. HTH, B PS: You should consider joining the Ifeffit mailing list: (http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit). It is a very useful resource for siftware and for XAS in general. On Saturday 07 November 2009 02:22:45 pm you wrote:
Dear Bruce Ravel,
I am a PhD student currently working with the ATHENA software. I came across a question which I could not answer even after searching the internet for hours. I hope you might have the time to briefly answer my question.
The self-absorption dialog requires the incoming (angle in) and the outgoing angle (angle out) as an input. My basic question is: Are these angles referenced to the sample surface or to the normal of the surface? I would not worry about that if I had measured in 45deg geometry (as in your tutorial example). However, I did not and therefore it makes a large difference.
I strongly apologize bothering you with such a basic question. Many thanks in advance. Best regards, Claudia Fleischmann
-- 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/