While I don't have much experience with biological samples in exafs, if you need to generate Ni - C paths, use the virtual path function in the new Dartemis which is very easy to use. Chris ******************************************** Dr. Christopher Patridge Assistant Professor of Chemistry Math and Natural Science Dept BFAC 009 D'Youville College 320 Porter Ave., Buffalo, NY 14150 716-829-8096 Sent from my iPhone

On Mar 18, 2014, at 4:13 AM, Sathish Mayanna wrote:

Dear all

So far, this forum has been very helpful for me to learn and understand how to fit EXAFS spectra of Mn oxides, thanks everyone for your suggestions.

Recently, I am working with Ni k-edge EXAFS and I have kind of similar question as Abhijeet Gaur (Ifeffit Digest, Vol 133, Issue 1), in my case, I am trying to fit EXAFS spectra of Ni(II) sorbed to bacterial biomass and Mn oxides (attached).

I followed the Matt suggestions by replacing Ni in place of Mn after running Atoms (birnessite model) to generate feff.inp.

I have two questions regarding this:

1) Ni(II) can be surface sorbed and or incorporated into Mn oxide structures. But, I cannot generate paths for this particular r-space. What and how can I edit the feff calculations? (attached).

2) Ni(II) sorp to bacterial biomass via some organic ligands (humic or carboxylic acids): The first shell mainly associates with Ni-O distances, there might be also Ni-C distances in later shells. I am wondering, how can I input the C in atoms or feff calculations?

I would be happy to receive your comments.

Regards Sathish

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