Re: [Ifeffit] XAS fitting

2019-10-11 Thread Mike Massey
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
> patri...@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
>> wan...@oregonstate.edu
>> 541-602-1707
>> ___
>> Ifeffit mailing list
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Re: [Ifeffit] XAS fitting

2019-10-11 Thread Chris Patridge
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
patri...@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
> wan...@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
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[Ifeffit] XAS fitting

2019-10-11 Thread Wang, Maoyu
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
wan...@oregonstate.edu
541-602-1707
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