[Ifeffit] Bug in Atoms

Bruce Ravel ravel at phys.washington.edu
Tue Mar 16 07:56:16 CST 2004

On Tuesday 16 March 2004 08:32 am, Schmithals wrote:
> I have attached an atoms.inp file that causes problems when used with
> Artemis. Both, Atoms run from within Athena as well as TkAtoms generate
> a feff.inp file with a wrong POTENTIALS-Card. Subsequently, FEFF will
> refuse to run, saying that potential number 1 is not used.
> I tried the same procedure with an older atoms.exe and had no problems.

Hmmm.... I really should fix this problem.  I am surprised at how infrequently 
people complain about this problem.  I suppose that is why I haven't got 
around to doing so yet.

The problem is that Atoms does not check to make sure that every item in the 
potentials list is actually in the atoms list.  (I think the old fortran 
version did make that check, but it somehow never got in the new version.)  

If you make Rmax in Atoms bigger, the problem will go away because the cluster 
will then be big enough to include all the atoms in the potentials list.  If 
you do not want to compute feff on such a large cluster, just set Rmax in 
feff.inp to something appropriate.  

The error message in feff is trigered when a potential does not appear in the 
atoms list.  However, it is not required that each item in the potentials 
list appear within rmax of the central atom.  As a rule of thumb, I would 
recommend setting Rmax to something large-ish in Atoms and use feff's rmax to 
actually restrict the number of feffNNNN.dat files that you compute.

> Another bug: TkAtoms allows only to open the space group browser only
> once. Every further click on "Browse space groups" will have no effect.

No kidding?  I'll look into it when I get home from NSLS.

Thanks as always for the great bug reports, Gerrit.

 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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