[Ifeffit] question about E0

[Shelly Kelly]

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 <janeth.lozano at gmail.com> wrote:
> 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 at 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 at iit.edu   http://www.iit.edu/~segre   segre at debian.org
>
>
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