[Ifeffit] Coordination number

Bruce Ravel ravel at phys.washington.edu
Thu Oct 30 16:01:40 CST 2003


On Thursday 30 October 2003 07:20 pm, Dave Baker wrote:
> I'm interested in extracting coordination numbers from the S02 parameter
> in Artemis, and, as the beginner, I'm lost as to what to do.  I am using
> two FEFF paths to describe the first shell, and have given each path its
> own S02 parameter.  Any suggestions?

There is some useful information from the mailing list archives on
this topic.

Go to my bug reports page:
  http://leonardo.phys.washington.edu/~ravel/software/exafs/bugs.html
and look for the "Common Q&A" box on the left side.  Question #2 is
relevant.

Another useful resource might be Chapter 10 from this document
  http://leonardo.phys.washington.edu/~ravel/course/notes.pdf
It suggests one simple strategy to the problem of two different
scatterers in the first shell.

In short, just throwing two separate amplitude parameters at the
problem in hopes that the numbers fall out to be physically
interpretable is probably not the best strategy.  You want to think of
some way to constrain the amplitude parameters for those two paths
in such a way that embodies the proper physics of the problem.

Once you've read over that material, don't hesitate to ask new
questions to the list.

B 

  
-- 
 Bruce Ravel  ----------------------------------- ravel at phys.washington.edu
 Code 6134, Building 3, Room 222
 Naval Research Laboratory                          phone: (1) 202 767 5947
 Washington DC 20375, USA                             fax: (1) 202 767 1697

 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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