[Ifeffit] Energy shift

["Dr. Dariusz A. Zając"]

Your attachment do not help in this case...
Do you know something more about sample? I suppose it is a thin layer. 
Have you checked if you have no defects, vacancies, etc?
I suppose that you can follow instructions given in this post 
http://millenia.cars.aps.anl.gov/pipermail/ifeffit/2009-January/008522.html
but you can be also interested in this topic: 
http://millenia.cars.aps.anl.gov/pipermail/ifeffit/2009-June/004293.html 
and especially in last posts.
you can also try this suggestion 
http://millenia.cars.aps.anl.gov/pipermail/ifeffit/2010-June/009471.html

In general - could you precise, what is k_{min} for your fit, and did 
you use self consistent potential in calculations?

  



W dniu 11-10-06 02:28, JeongEunSuk pisze:
> Thank Dariuz and Bruce.
> TiO is deposited on Si substrate and PtO is fabricated on TiO2.
> I measered EXAFS with Pt L3 edge(11563eV) and The model is decided 
> from FEFF8.0.
> PtO has only fist shell like attached files So I chose the simple 
> model with octahedral structure (probe atom Pt, others O)
> When the EXAFS was fitted by feffit, the variables were three eo(Enot 
> in Artemis, energy shift), do1(distance factor), sigo1(debye-waller 
> factor).
>  the results of fit is as following
> variable            best fit value    uncertainty  initial guess
>        eo             =       19.283398        1.726426        0.000000
>        do1            =       -0.023227        0.009557        0.096000
>        sigo1          =        0.003790        0.000583        0.003047
> r-factor: 11
> reduced-chi square: 95
>
> Energy shift by fit shows an amount of difference from Pt L3 edge.  It 
> is my problem.
> To reduce the energy shift, I tried to remove background carefully 
> again  and to change distance Pt-O.
> However the result was failed.
>
>
>
> ------------------------------------------------------------------------
> Date: Wed, 5 Oct 2011 08:24:16 +0200
> From: kicaj at ifj.edu.pl
> To: ifeffit at millenia.cars.aps.anl.gov
> Subject: Re: [Ifeffit] Energy shift
>
> Hi,
> could say more precise what kind of energy shift you are talking 
> about? the position of the white line or the Enot in Artemis. How big 
> it is? Which version of Feff do you use? What do you mean writing 
> "removing background carefully"? Background in the EXAFS fit? Any 
> pictures to illustrate problem are welcome
>
> W dniu 11-10-05 03:25, JeongEunSuk pisze:
>
>     Hell all
>     I have the study for PtO nanoparticles with EXAFS.
>     When I fitted the data to model, I had a problem for energy shift.
>     I thought that the energy shift obtained from fitting must be
>     below White line. However it was over white line.
>     Although I removed background carefully and changed bond length in
>     model, the energy shift was still big.
>     I want to know other factors which affect energy shift.
>
>
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