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RE: a wacky idea from me and Matt
Kind of stone age, but "good enough" is a concept I've always liked.
Speaking of "good enough", how different are the FEFF8 central atom
tables from those generated by the old FEFF3 or FEFF6?
-----Original Message-----
From: Bruce Ravel [mailto:ravel@phys.washington.edu]
Sent: Wednesday, February 13, 2002 3:42 PM
To: FEFF Software Development
Subject: a wacky idea from me and Matt
Howdy folks,
I wanted to draw your attention to a side project that Matt and I have
started. Take a look at
http://leonardo.phys.washington.edu/~ravel/software/feff_tables/
The idea of this project is to recreate the old feff tables using FEFF8.
How's that for a loony idea?
There really is a good reason for needing something light-weight like
the old feff tables (or the similar tables from McHale or Teo and Lee).
Sometimes one needs some quick 'n' dirty phase shifts and/or amplitudes
in a situation where the overhead of even a feff6 calculation is just
too much.
The thing that motivated this is Athena, the GUI data processing utility
that I am working hard on these days. I want to include the possibility
of displaying Fourier transforms corrected by the central atom phase
shift. Without getting into a discussion of whether that is really
desirable, it requires having some kind of info about the central atom
phase shift. Because Athena is a data processing utility and NOT a data
analysis utility, it is not reasonable to expect someone using Athena to
run feff and read in a feffNNNN.dat file just for the sake of phase
corrected transforms. My solution is to create a database of central
atom phase shifts computed in some crude manner. The details of the
calculations are described on the web page. The phase shifts in this
calculation are obviously inadequate for real analysis, but they should
be "good enough" for displaying phase corrected transforms.
Matt and I are open to comments on these tables. The little program I
wrote to generate the tables is on the web page as are flat text files
containing the data. Perhaps this may be useful to someone else...
Regards,
B
--
Bruce Ravel -----------------------------------
ravel@phys.washington.edu
U.S. Naval Research Laboratory, Code 6134 phone: (1) 202 767
5947
Washington DC 20375, USA fax: (1) 202 767
1697
NRL Synchrotron Radiation Consortium (NRL-SRC)
Beamlines X11a, X11b, X23b, X24c, U4b
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/