[Ifeffit] Several Questions
Edward L. Kunkes
kunkes at wisc.edu
Wed Apr 18 10:55:22 CDT 2007
I am currently using IFEFFIT to fit LIII edge data collected for Pt, Re
and PtRe bi-metallic Nan particles supported on carbon, and I have several questions:
1. I get an So2 value of 0.54 from a first coordination shell fit on
Re-foil (this So2 value also seems to work when fitting NH4ReO4-)
Has anyone ever worked with Re before and gotten a similar value for So2 ?
2. I model the path for the a single coordination shell as 6 octahedrally
arranged nearest neighbor atoms surrounding the absorber atom at a distance
equal to that of inter -atomic spacing in the metal. When comparing the IFEFFIT
predicted EXAFS for this model to one that is generated by using the first path from
a crystallographic model, the two seem slightly different. The nanoparticles are
very small (amorphous to XRD), and probably consist of a disordered phase, so I cannot
assign a crystal structure. What should I do in this case?
3. I often get high correlations the coordination number and ss, or delEo and dR
(the correlations are ~0.8). Using multiple k-weights doesn’t decrease the correlations.
What is an acceptable value for these correlations?
Thank you very much for taking the time to answer my questions
More information about the Ifeffit