Hi Shoaib, On Wed, Jun 25, 2014 at 7:34 AM, Shoaib Muhammad wrote:

Dear Matt Newville,

Sorry to disturb you by asking one question, hopefully you will mind it.

I often see that resolution XAFS spectrum of K-edge and especially

Asking on the ifeffit mailing list is generally better. I am CCing this reply to that list. pre-edge is good for

3d transition metal but comparatively 4d transition metal XAFS spectra and its pre-edge spectrum is poor. Is it due to low energy resolution at higher energy level at synchrotron source or something related with electronic transitions? because as far I understand pre-edge in 3d transition metal is due to 1s-3d and 4d metals is 1s-4d.

The energy resolution is a convolution of monochromator energy resolution and natural line-width of the core electronic level. Generally speaking, for K edges below 10 keV or so, Si(111) and the core-level widths are comparable, ranging from ~0.5eV to 2 eV. Both the mono resolution and core-width increase with energy, but the core-width increases quadratically and so tends to dominate at higher energies (say, above 20 keV). Core level widths for L3 edges are about 2x that of K edges, so that this term almost always dominates for L3 edges.

I am student in Sungkyunkwan University (Korea) and a beginner of XAFS.

Cheers, --Matt