Matthew, Matt, and Anatoly,
Thanks for your replies and some good suggestions. You have convinced me
that the best thing for me to do here is to try multiple analysis methods
and see how well the results, and uncertainties, compare, as was done in
the previously referenced PRL.
Thanks again,
Something I've done for analyzing DWF on data taken at several
temperatures is what I called 'consensus amplitude' fitting. Here, I
fitted shells to
k^n*chi[i](k) = exp(-2 dsig2[i] k^2) A(k) sin(phi(k)+2 dr[i]k)
where i is the index to temperature, and the fit parameters are A(k),
phi(k),
Hi George,
I think this will not be a different answer from Matthew's or Anatoly's
answers, but just reiterate their points. The Purans et al 2008 PRL from
2008 appears to use both non-linear fitting with Feff and EDA (which should
give basically the same results as Artemis/Ifeffit/Larch, though
Matthew,
In the paper by Purans et al that George references, they showed that the
FEFF fitting method and ratio method agreed, and in the ratio method the
amplitudes and phases are extracted from experimental standards, just as in
your paper.
Anatoly
On Sat, Apr 11, 2020 at 2:21 PM Matthew
The uncertainties reported by Artemis include as 'noise' the systematic
deviation of FEFF calculation from the real thing. Even if FEFF were
perfect, those FEFF calcs haven't been through the mutilations inflicted
by data reduction, such as spline fitting. What I've done when looking
at
Hello,
As is well known, EXAFS is more accurate at determining relative changes in
bond lengths than absolute changes in bond lengths due to cancelation of
systematic errors in relative comparisons. When comparing the relative
changes in bond lengths determined from EXAFS fits, as one might for a
