Re: [Ifeffit] XAS fitting

The short, short version, in my estimation, is "pick two paths as a reasonable starting point and let the fitting parameters do the rest." You could even use two clones of the same path, which will end up getting different CNs, delr, and ss in the fit. There's no law that says you have to use Feff paths that correspond to paths in your structural model (if an analogous path even exists). As long as it's close-ish to start (the program will throw a warning if it's not close enough), the fitting parameters can be used to handle small differences arising from e.g., octahedral vs tetrahedral coordination.

On Oct 12, 2019, at 12:39 PM, Chris Patridge wrote:

You can run two calculations and import the paths and scale the contributions from each site. There are a lot of examples and this has been discussed before on the mailing list if you search.

Hope that helps,

Chris

********************************************* Dr. Chris Patridge Assistant Professor Department of Chemistry SASE 315 D’Youville College 320 Porter Ave Buffalo, NY 14201 716-829-8096 patridgc@dyc.edu

...

On Oct 11, 2019, at 6:34 PM, Wang, Maoyu wrote:

Hi

I am running an EXAFS fitting for spinel Co3O4. As we know, the Co3O4 will have two different two local coordinations. One is 6 Co-O coordinated octahedral site, and another one is 4 Co-O coordinated tetrahedral site. When we run the Feff calculation, we can only use one Co site to do the calculation once, and we can only get one site coordination by one calculation. However, the EXAFS will tell us the average local structure. How could we use these two different calculation paths to do the fitting?

Sincerely,

Maoyu Wang Chemical Engineering Oregon State University wangma@oregonstate.edu 541-602-1707 _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

---

Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit