Hi Shoaib,
On Wed, Jun 25, 2014 at 7:34 AM, Shoaib Muhammad <
mshoaibce@gmail.com> wrote:
>
> Dear Matt Newville,
>
> Sorry to disturb you by asking one question, hopefully you will mind it.
Asking on the ifeffit mailing list is generally better. I am CCing this reply to that list.
> I often see that resolution XAFS spectrum of K-edge and especially 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).