[Ifeffit] weights data processing
Bruce Ravel
ravel at phys.washington.edu
Mon Jul 26 08:06:13 CDT 2004
I wanted to add a coupe more comments on Stafano's questions regarding
k-weighting in Athena and Artemis.
Regarding k-weights in Athena: Athena's default for the k-weight using
background removal is 1. I chose that pretty much for the reason that
Scott gave. Ifeffit's default is 0, so this is a situation where
Athena and Ifeffit have different default behavior. As for the
insensitivity of your data to this value, I would say that it is
situational. Sometimes, the k-weight can have a dramatic influence on
the background removal. Stability of the background removal and its
impact on subsequent analysis has been a frequent topic of discussion
in this forum. k-weight, then, is yet another parameter that can
impact the stability of your spline.
Rgearding k-weights in Artemis: Scott and Matt covered the "why" of
k-weights. How k-weights are actually used by Artemis when fitting
and plotting is a bit complicated. See section 5.8.4 of the
(incomplete) artemis document for a detailed explanation of how
k-weighting is used in Artemis.
http://leonardo.phys.washington.edu/~ravel/software/exafs/doc/artemis.pdf
B
--
Bruce Ravel ----------------------------------- ravel at phys.washington.edu
Code 6134, Building 3, Room 405
Naval Research Laboratory phone: (1) 202 767 2268
Washington DC 20375, USA fax: (1) 202 767 4642
NRL Synchrotron Radiation Consortium (NRL-SRC)
Beamlines X11a, X11b, X23b
National Synchrotron Light Source
Brookhaven National Laboratory, Upton, NY 11973
My homepage: http://feff.phys.washington.edu/~ravel
EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/
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