[Ifeffit] Plotting chi(k) linear combination fit in energy

Scott Calvin scalvin at sarahlawrence.edu
Mon Jul 20 20:15:29 CDT 2015

Hi Ellen,

Either I’m not understanding what you’re trying to do, or what you’re trying to do doesn’t make sense.

XANES is generally plotted as mu(E) or norm(E). To get from norm(E) to chi(k), two things must be done: a smooth background must be subtracted from norm(E), and E has to be converted to k. The conversion from E to k is reversible, but the background subtraction is not, since chi(k) is meant to be background independent. You therefore cannot, in principle, plot chi(k) data as norm(E).

—Scott Calvin
Sarah Lawrence College

On Jul 20, 2015, at 7:48 PM, Ellen Daugherty <ellen.daugherty at colostate.edu<mailto:ellen.daugherty at colostate.edu>> wrote:


I was unable to find an example of this question in the archive, but please let me know if it has already been addressed. I would like to plot the results of linear combination fits performed in chi(k) in energy space to compare them to XANES fits. When I try to plot the saved fit in energy, I get a message saying: "chi data cannot be plotted in energy." Is there any way to do this other than to use Excel to scale the weights of the standards? This would be exhausting to perform for combinatorial fits. I am using Athena in Demeter 0.9.20 on Windows 7. I have attached a sample and a few standards for aid in addressing the issue.

Thank you!


Ph.D. Candidate
Research Assistant, Borch Lab<http://borch.agsci.colostate.edu/>
Department of Chemistry
Colorado State University
<Sample.nor><Standard 1.nor><Standard 2.nor><Standard 3.nor>_______________________________________________
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