[Ifeffit] Large Enot values

Paul Bingham p.a.bingham at sheffield.ac.uk
Tue Jun 8 17:55:04 CDT 2010

Thanks Bruce,

I agree that the Se-O bond lengths are short but in SeO2, and Na2SeO3 as Se4+
"standards" there are Se-O bond lengths average around 1.7A. For example when I
run feff on the SeO2 cif file it gives 1 Se-O bond at 1.623A and 2 at 1.793A,
averaging at roughly 1.7A. 

I'm confident that the XANES I have for this sample show that the Se is pretty
much all present as Se4+ and I think the first shell is very likely to consist
of oxygens.

I also tried another shell from the same feff as included in the data I sent,
using O1_1 instead of O2_1 and the fit including Delr still points to an
average Se-O bond length of about 1.7A with an Enot of around 10.

I will try fitting with feffs based on different cif files with some different
Se-O bond lengths, but if you have any other suggestions I'd be grateful.

Thanks very much for your advice - it's appreciated.


Dr. Paul Bingham
Postdoctoral Research Associate
Immobilisation Science Laboratory
Dept. of Engineering Materials
University of Sheffield
Mappin Street
S1 3JD

Email: p.a.bingham at sheffield.ac.uk
Direct Line: (0114) 2225473

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