[Ifeffit] multiple fits

[Kelly, Shelly D.]

Hi Stefano,

> 
> I have the following question: let's say I have a data set for which 
> I would like to try a long series of possible models and monitor the 
> result of the fits. The models are geometric variations of a 
> starting structure.I have all related feff.inp files for each model 
> ready.  Is there a way to process the data so that I can get out the 
> related fits? I do not think I can do this using artemis, but maybe 
> there is a set of commands to be given from the command line?
> 
> Thanks
> Stefano

The short answer is no.

The long answer is sure.  But the script that you need to write is long
and complicated.  You have to teach the computer how to model the
structure for all the variations so that it will make the appropriate
variables to determine in the fit, and also how to handle the output.
These tools are not incorporated into ifeffit.  

I am responding to your request, because I did this as a graduate
student.  Back in the old days, I was using atoms, feff, and feffit.
The program that I wrote moves the atoms in a unit cell, writes out a
atoms.inp file, runs atoms, runs feff, makes a feffit.inp file and runs
a fit, and then makes a spread sheet to compare the answers.  If you are
interested, I wrote is a small EXAFS paper about this script, and would
be happy to share.

S.D. Kelly, R. Ingalls, and E. A. Stern, "Determining crystalline atomic
positions using XAFS, a new addition to the UWXAFS analysis package,"
Journal of Synchrotron Radiation. 8 311-313, 2001. 

In the end, I think that you will agree that you have a lot of work
ahead of you.  

HTH
Shelly