On Tuesday 12 July 2005 07:15, Dr. K.R.S. Priolkar wrote:

Hi I wouldlike to know if it is possible to refine Ce L1 edge EXAFS using Artemis wherein there is a contribution of Ce L2 EXAFS.

If yes, how to go about it?

Kaustubh Wow. That's an interesting question. I have to confess that I have never given this a lot of thought, but it seems like something that should be possible. Before suggesting two possible solutions, I want to mention that those two edges are about 380 volts, or 10 inverse angstroms, apart. The wiggles from the L2 edge should be quite low frequency by the time the L1 edge shows up. It is possible that the background removal algorithm at the L1 edge will remove most (maybe even all) of the contribution from the L2 edge because the L2 oscillations will be below the frequency of the first shell. Of course, the L1 edge is really tiny, so the L2 might still be a big effect. My first suggestion is to fit the L2 edge as best you can using Artemis (assuming, perhaps without merit, that the L3 signal does not get in the way). Let Artemis write out the fitted chi spectrum out to, say 15 inverse angstroms. Then subtract the portion of the fitted L2 chi spectrum from the L1 data in the region where they overlap. My second suggestion is to run Feff for the L2 edge from within Artemis and apply an enormous e0 shift to the paths from the L2 calculation. I have no confidence that such a large e0 shift will really work the way you want, though. Anyone else have any clever ideas for solving this with existing technology? Any suggestions for improvements to Artemis to facilitate this sort of thing? B -- Bruce Ravel ----------------------------------- bravel@anl.gov -or- ravel@phys.washington.edu *** My cell phone number has changed. Please ask if you need the new number Environmental Research Division, Building 203, Room E-165 Argonne National Laboratory phone and voice mail: (1) 630 252 5033 Argonne IL 60439, USA fax: (1) 630 252 9793 My homepage: http://feff.phys.washington.edu/~ravel EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/