[Ifeffit] XANES - Peak assignment and ionization potential with FEFF

Ross Devol devol at wisc.edu
Tue Sep 17 00:42:57 CDT 2013

Thanks Bruce! That answers my first question.
What about ionization potential? Does FEFF calculate it, or is there a way to extract it from the spectra?

On 09/13/13, Bruce Ravel 
> On 09/13/2013 03:25 PM, Ross Devol wrote:
> >Does anyone know whether FEFF can be used to assign peaks? In other
> >words, is there a way to tell which peaks in a calcite O K-edge
> >spectrum are due to CO bonds and which to CaO bonds? Also, does
> >FEFF calculate the ionization potential and if so, where does it
> >output this?
> Feff is a real-space multiple-scattering code. From the RSMS, your
> question may not make a lot of sense. The XAS spectrum is a measure
> of how the photoelectron interacts with its surroundings. In general,
> peaks in the spectrum have something to do with all of the surroundings.
> One way to get a handle, in some sense, on your question is to run
> Feff with successively larger values of the FMS parameter. That is,
> see what features appear or change in the calculation as you increase
> the radius of the cluster considered in the FMS calculation.
> Also of interest will be the partial densities of state as a function
> of cluster size. That gives some hints of how Feff sees bonding in
> your cluster.
> HTH,
> B
> -- 
> Bruce Ravel ------------------------------------ bravel at bnl.gov
> National Institute of Standards and Technology
> Synchrotron Science Group at NSLS --- Beamlines U7A, X24A, X23A2
> Building 535A
> Upton NY, 11973
> Homepage: http://xafs.org/BruceRavel
> Software: https://github.com/bruceravel
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