[Ifeffit] EXAFS mean free path in small particles
John J. Rehr
jjr at leonardo.phys.washington.edu
Mon Jun 20 12:11:04 CDT 2005
Hi Matt,
Thanks for the interesting Cu fits.
Clearly the coorrelations between S02, ThetaD and Ei make any
assessment of possible problems with Ei problematic. Also, I don't
know what the experimental resolution Gamma_expt is - probably some
fraction of an eV, so Ei=Gamma_expt+Im delta Sigma implies a comparable
but negative correction delta Sigma to the self-energy, which is
evidence of excessive loss in the HL plasmon-pole self-energy for Cu.
Moreover, although your fits are in R-space, inspection of the k-space data
shows that contributions from distant MS paths are suppressed by the theory,
also suggesting that FEFF's PP self-energy overestimates loss.
It will be interesting to see what Ei does if one forces S02=0.9
(based on Luke Campbell's theoretical estimate) and ThetaD=315 K.
We'll also try to make an independent fit using the Bayesian/EXAFS+XANES
scheme that we're working on here.
J. Rehr
> |-----------------------------------------------------------------|
> |Fit S02 ThetaD Ei E0 dR chi_reduced|
> |-----------------------------------------------------------------|
> |#1 0.93(0.03) 271(12) 0.0( - ) 0.7(0.4) -0.003(0.002) 12.8 |
> |#2 0.78(0.09) 300(23) -1.5(0.9) 0.7(0.3) -0.003(0.001) 10.9 |
> |-----------------------------------------------------------------|
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