Hi Jin, I am CCing my response to the Ifeffit mailing list: http://cars9.uchicago.edu/mailman/listinfo/ifeffit/ If you are not already a member of the mailing list, I encourage you to join. It is a great place to ask questions and learn about XAFS and the Ifeffit-based software. On Sunday 16 September 2007, you wrote:

Dear Ravel:

I am just a student of Shanghai Applied Physics Institute, CSA. And I meet some problem by using FEFF process.

When I know the coordination number and the coordination distance of known structure macular, how to set the atom inp file or feff inp file?

I'm afraid that I am little unsure what you exact question is. If you know the coordination number and distance because your material is a known crystal, then you can just use a CIF file or an atoms.inp file of the sort described here: http://cars9.uchicago.edu/~ravel/software/doc/Atoms/Atoms/node4.html or available for many materials at this database: http://cars9.uchicago.edu/~newville/adb/search.html If you know coordination and distances because you have structural information of the sort that you might find in a protein data bank file or some other molecular format, then you should skip the use of atoms and simply convert the molecular data to a feff.inp file as described on page 36 of this talk I recently gave: http://cars9.uchicago.edu/~ravel/talks/pimst2.pdf It is important to remember that Atoms is a tool for converting crystallographic data into a list of atomic coordinates. That's all it does. If you are doing XAFS on something that is not a crystal, Atoms is of no use.

And another question is how get the usefully muffin tin from the XRD data in the protein data bank?

Feff computes muffin tins. In 99% of all situations, you do not need to modify how Feff does tht nor do you need to specify muffin tin radii. Feff's algorithm for determining muffin tin radii given a list of atomic coordinates is relatively simple, but surprisingly effective and completely automated.

I have tried many time as the handbook shows, but I also don't know how to do? So I need your help ? Thank you very much

You may find it useful to ask explicit questions on the mailing list by posting examples of the problem you are having. For instance, if you are having trouble running Feff, asking a question about the exact thing that is confusing and posting an example of the feff.inp file that is giving you trouble will help the people on the mailing list help you. Good luck and I hope this was helpful, Bruce

Smiling everyday,

Best wishes,

Jin Chan

-- Bruce Ravel ---------------------------------------------- bravel@anl.gov Molecular Environmental Science Group, Building 203, Room E-165 MRCAT, Sector 10, Advance Photon Source, Building 433, Room B007 Argonne National Laboratory phone and voice mail: (1) 630 252 5033 Argonne IL 60439, USA fax: (1) 630 252 9793 My homepage: http://cars9.uchicago.edu/~ravel EXAFS software: http://cars9.uchicago.edu/~ravel/software/