[Ifeffit] Fitting EXAFS simulation to experimental

[Bruce Ravel]

On 05/28/2014 06:58 PM, Carl Brozek wrote:
> Dear listhost,
>
> I'm using Artemis as a front end for ATOMS and FEFF and I would like to
> build a simulated EXAFS spectrum based on experimental data I have. I
> know how to generate a simulation based on a .cif or .xyz file, but is
> it possible to vary parameters in these input geometries to best match
> the experimental?
>
> Has someone implemented this in artemis or matlab?
>
> thanks,


Carl,

In Artemis, this is called a VPath.

   http://bruceravel.github.io/demeter/artug/plot/vpaths.html

You will need to import data of some sort because a VPath is created
from paths that have been associated with a data set.

Run Feff.  Drag and drop any number of paths from the Path tab in the
Feff window onto your data Window.  Mark the paths paths you want to
include in your VPath by clicking their little check buttons.  From
the Actions menu, select "Make VPath from marked".  This will prompt
you for a name for the VPath and insert the VPath into the plotting
list, as described in the page whose URL is given above.

As for varying structural parameters, that is what we call a "fit".
You can parameterize the various Delta R parameters to represent
changes in lattice positions.  There are plenty of examples of this
using Ifeffit -- Daniel Haskel's papers on cuprate superconductors, my
own papers on titanate perovskites, lots of work buy Anatoly Frenkel
on various catalyst materials, Sam Webb's work on manganites, just to
name a few.

B



-- 
  Bruce Ravel  ------------------------------------ bravel at bnl.gov

  National Institute of Standards and Technology
  Synchrotron Science Group at NSLS --- Beamlines U7A, X24A, X23A2
  Building 535A
  Upton NY, 11973

  Homepage:    http://xafs.org/BruceRavel
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