a wacky idea from me and Matt

[Bruce Ravel <ravel@phys.washington.edu>]

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/