Hi Matt, I should have given these details right away. My trick is to parameterize the feff paths in terms of an x, y, z coordinate for the atom on the surface. Then I refine three different polarization dependent data sets to find the best x, y, and z position of the atom on the surface. Thanks for the references! Shelly

-----Original Message----- From: Matt Newville [mailto:newville@cars.uchicago.edu] Sent: Thursday, July 21, 2005 11:13 AM To: Kelly, Shelly D.; XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] surface EXAFS

Hi Shelly,

...

I am working on a project were I trick feffit into moving an atom around on the surface of a plane to refine polarization dependent surface EXAFS data. I made a quick literature search and have not found any other EXAFS papers that do such a thing. Are you aware of similar work? I would like to give credit in our manuscript.

I know of other work in progress (some in progress for a pretty long time!!). I also believe there are a few surface XAFS papers that used feffit. I think these may count, though I don't have a copy of any of these in front of me:

L. Y. Zhao et al, Applied Surface Science 228, p 257 (2004) P. Luches et al, Surface Science 566, p 84 (2004) L. Damoc, et al J. Applied Physics 92, p 1862 (2002) S. K. Kim, et al, PRB 62, p 3025 (2000).

I think there are probably others.

I'm not sure what the 'trick' you're using is. Doing a polarized calculation (with feff or in feffit) for an atom on a surface doesn't seem like such a big deal, but maybe you're doing something fancier.

One paper that I know is in progress (and a just-completed thesis) measures the 'height above the surface' of a sorbed atom by defining several different distances in terms of this height.

--Matt