[Ifeffit] lifetime broadening of pre-edge peaks?
newville at cars.uchicago.edu
Mon Oct 10 08:41:07 CDT 2011
On Sat, Oct 8, 2011 at 4:36 PM, Matthew Marcus <mamarcus at lbl.gov> wrote:
> Is the core-hole lifetime broadening of pre-edge XANES peaks the same as at
> the main edge? I'm looking into issues of de-noising of XANES epsctra, so
> need to figure out how narrow real features can be.
I'm sure others are more knowledgeable about this, but I think the
answer is the classic "yes, but...". The "yes" part would be: Yes,
the core-hole energy width doesn't depend on the final state.
The "but" part would be: But that assumes (I think) that the final
state has lost all connection to the core level, except the principle
quantum number (that is, it has to be p-like for an s hole). That
assumption isn't exactly true for bound atomic/molecular states that
give the pre-edge peaks, as there is some spin information preserved.
I think regular XANES measurements of the pre-edge peaks do include
the full core-hole lifetime. But, has been demonstrated many times,
with high-energy resolution of the emission (RIXS), one can beat the
core-hole lifetime, as the energy-selected emission can come from only
a limited portion of the full core-hole energy width.
Hopefully, someone will correct any errors in this...
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