Hi everybody, My question is about the E0, i am making fits where the E0 final is some high, around 8eV, i tried to change the feff calculation with the card EXCHANGE to lower the E0 but it did not work, after the fit i obtained the same E0 around 8 eV, what can i do to improve the E0 around 5 eV, any suggestion? Distance and sigmas are reasonable but my E0 not at all Thanks Janeth Lozano PhD Student mlozano@mda.cinvestav.mx
Hi Janeth: On Wed, 19 May 2010, Janeth Lozano wrote:
My question is about the E0, i am making fits where the E0 final is some high, around 8eV, i tried to change the feff calculation with the card EXCHANGE to lower the E0 but it did not work, after the fit i obtained the same E0 around 8 eV, what can i do to improve the E0 around 5 eV, any suggestion? Distance and sigmas are reasonable but my E0 not at all Thanks
It would be very helpful if you could send an artemis project file to the list. That would help us answer your question. Sometimes, the value of E0 is just a bit bigger than you would like and it is OK (more or less). Other times it is an indication that there is something amiss with your fit. it is hard to tell without looking at the data. Cheers, Carlo -- Carlo U. Segre -- Professor of Physics Associate Dean for Graduate Admissions, Graduate College Illinois Institute of Technology Voice: 312.567.3498 Fax: 312.567.3494 segre@iit.edu http://www.iit.edu/~segre segre@debian.org
Hi Carlo You´re right, sorry for didn´t send the artemis project file, thanks for your soon answer cheers Janeth Lozano PhD student mlozano@mda.cinvestav.mx On May 19, 2010, at 8:03 PM, Carlo Segre wrote:
Hi Janeth:
On Wed, 19 May 2010, Janeth Lozano wrote:
My question is about the E0, i am making fits where the E0 final is some high, around 8eV, i tried to change the feff calculation with the card EXCHANGE to lower the E0 but it did not work, after the fit i obtained the same E0 around 8 eV, what can i do to improve the E0 around 5 eV, any suggestion? Distance and sigmas are reasonable but my E0 not at all Thanks
It would be very helpful if you could send an artemis project file to the list. That would help us answer your question. Sometimes, the value of E0 is just a bit bigger than you would like and it is OK (more or less). Other times it is an indication that there is something amiss with your fit. it is hard to tell without looking at the data.
Cheers,
Carlo
-- Carlo U. Segre -- Professor of Physics Associate Dean for Graduate Admissions, Graduate College Illinois Institute of Technology Voice: 312.567.3498 Fax: 312.567.3494 segre@iit.edu http://www.iit.edu/~segre segre@debian.org
Hi Janeth,
The value for deltaE0 from the fit to the chi(k) data is directly
related to the value of E0 you choose when you remove the background
in Athena. This is what defines k=0 in the chi(k) data. So if you
change the E0 in the background removal step you should be able to
change deltaE0 in the fitting result. I have a small EXAFS conference
paper that shows how to do this. I also have an example in my book
chapter (figures 33 and 34). But it really isn't hard, just try it
and it will work.
1. Kelly, S. D. and Ravel, B. (2007). EXAFS energy shift and
structural parameters. 13th International Conference on X-ray
Absorption Fine Structure. Hedman, B. and Pianetta, P. Melville, NY,
American Institute of Physics Conference Proceedings. 882: 132-134.
If you want a copy of the book chapter or a reprint of the article
just send me a personal email.
HTH,
Shelly
On Thu, May 20, 2010 at 6:06 AM, Janeth Lozano
Hi Carlo
You´re right, sorry for didn´t send the artemis project file, thanks for your soon answer
cheers
Janeth Lozano PhD student mlozano@mda.cinvestav.mx
On May 19, 2010, at 8:03 PM, Carlo Segre wrote:
Hi Janeth:
On Wed, 19 May 2010, Janeth Lozano wrote:
My question is about the E0, i am making fits where the E0 final is some high, around 8eV, i tried to change the feff calculation with the card EXCHANGE to lower the E0 but it did not work, after the fit i obtained the same E0 around 8 eV, what can i do to improve the E0 around 5 eV, any suggestion? Distance and sigmas are reasonable but my E0 not at all Thanks
It would be very helpful if you could send an artemis project file to the list. That would help us answer your question. Sometimes, the value of E0 is just a bit bigger than you would like and it is OK (more or less). Other times it is an indication that there is something amiss with your fit. it is hard to tell without looking at the data.
Cheers,
Carlo
-- Carlo U. Segre -- Professor of Physics Associate Dean for Graduate Admissions, Graduate College Illinois Institute of Technology Voice: 312.567.3498 Fax: 312.567.3494 segre@iit.edu http://www.iit.edu/~segre segre@debian.org
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participants (4)
-
Carlo Segre -
Janeth Lozano -
Janeth Lozano -
Shelly Kelly