[Ifeffit] Error in second shell fit

Christopher Patridge patridge at buffalo.edu
Wed Feb 20 11:21:18 CST 2013


Dev,

Attached is a screenshot of the Data window of D-Artemis.  The area 
highlighted is the Rmax that the error refers to.  You change this value 
to near the reff of the 2nd shell and the error will disappear!

Chris

********************************
Christopher J. Patridge, PhD
NRC Post Doctoral Research Associate
Naval Research Laboratory
Washington, DC 20375
Cell: 315-529-0501

On 2/20/2013 11:13 AM, Christopher Patridge wrote:
> Dev,
> As Bruce points out, the error message is somewhat ambiguous.  There 
> is a setting in (D)Artemis, completely separate from the Feff 
> calculation, that allows one to set the range in R-space of your data 
> that is fit with the chosen paths you include from the Feff calculation.
> I would also say that this is not really an error, per se, but more of 
> an warning.  I am not at my computer right now but I will  send a 
> highlighted screen show of Artemis and where one would change 
> the R-space range value for rmax.
> I hope that clears up the confusion,
> Chris
>
> On Wed, Feb 20, 2013 at 10:54 AM, Devender <devend at rpi.edu 
> <mailto:devend at rpi.edu>> wrote:
>
>     Dr. Patridge,
>
>     Thanks for suggestion. I am not sure if I get completely, I do
>     understand the difference of Rmax in artemis and feff. You mean
>     make changes in rmax in feff input file? I did that and attached
>     are screenshots for that but I am still getting the same error.
>     Let me know if I interpreted your suggestion wrongly.
>
>     Dr. Kicaj, I am studying doping problems and it's important I get
>     fitting from second and subsequent shells as there are new peaks
>     that shows up at higher radial distances.
>
>     Regards,
>     Dev
>
>
>     On Wed, Feb 20, 2013 at 8:26 AM, Christopher Patridge
>     <patridge at buffalo.edu <mailto:patridge at buffalo.edu>> wrote:
>
>         Dev,
>
>         I don't know if my email was received.  The think the problem
>         is what you interpret as rmax.  Rmax in artemis is the maximum
>         value of R that you fit the data with, whereas rmax in feff is
>         the largest distance from the center absorbing when
>         calculating all the paths.
>
>         The reason changing the rmax in feff does remove the error is
>         that you must change the fitting range in (D)Artemis.  I think
>         the default vaue is ~ 3 A.
>
>         Chris
>
>         ********************************
>         Christopher J. Patridge, PhD
>         NRC Post Doctoral Research Associate
>         Naval Research Laboratory
>         Washington, DC 20375
>         Cell:315-529-0501  <tel:315-529-0501>
>
>         On 2/20/2013 3:13 AM, "Dr. Dariusz A. Zając" wrote:
>>         Dev,
>>
>>         I work with older Ifeffit version thus I can not help you
>>         much - I can not open (Artemis) or work (Athena) with projects...
>>         I have only one question - do you need to fit paths about 4A?
>>
>>         I hope that someone on this mailing list will check your files
>>
>>         regards
>>         kicaj
>>
>>
>>         W dniu 13-02-19 17:47, Devender pisze:
>>>         Dr. Kicaj,
>>>
>>>         I tried that too, went till 8 A, but it is still showing
>>>         same error whereas R effective for second shell paths are
>>>         4.4 and 4.7 A. I have also attached athena file and artemis
>>>         project file for my data for reference.
>>>
>>>         -Dev
>>>
>>>         On Tue, Feb 19, 2013 at 10:57 AM, "Dr. Dariusz A. Zając"
>>>         <kicaj at ifj.edu.pl <mailto:kicaj at ifj.edu.pl>> wrote:
>>>
>>>             Hi,
>>>
>>>             could you check if the same  error appears if you give
>>>             the Rmax of, let's say, 8A or even 6.5A?
>>>             For higher R, the paths sometimes does not look like a
>>>             single "gaussian" peak, but has some kind of
>>>             "satellites". You have to also remember that each path
>>>             consists of the real and imaginary part.
>>>
>>>             Regards
>>>             kicaj
>>>
>>>
>>>
>>>             W dniu 13-02-19 16:42, Devender pisze:
>>>>             Hi,
>>>>
>>>>             I am trying to fit Bi2Te3 exafs data using artemis. I
>>>>             am able to fit first shell (screenshot of fit is
>>>>             attached, I have also attached 'atoms' and 'feff' files
>>>>             for reference) but when I am trying to include second
>>>>             shell, I am getting the error (attached file-
>>>>             Fit_error.log). Error reads that- "The R effective for
>>>>             this path is well beyond the rmax value of its Data
>>>>             object." but I am already using Rmax of 6 A and Reff of
>>>>             these path are less than 5 A in my fit. I will
>>>>             appreciate if anyone can guide me or point me where I
>>>>             am making mistake.
>>>>
>>>>             Regards,
>>>>             -- 
>>>>             Devender
>>>>             Graduate Student, Materials Science and Engineering
>>>>             Rensselaer Polytechnic Institute, Troy, NY
>>>>             Website <https://sites.google.com/site/devendermaun/>
>>>>
>>>>
>>>>
>>>>             _______________________________________________
>>>>             Ifeffit mailing list
>>>>             Ifeffit at millenia.cars.aps.anl.gov  <mailto:Ifeffit at millenia.cars.aps.anl.gov>
>>>>             http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>>>
>>>
>>>             _______________________________________________
>>>             Ifeffit mailing list
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>>>
>>>
>>>
>>>
>>>         -- 
>>>         Devender
>>>         Graduate Student, Materials Science and Engineering
>>>         Rensselaer Polytechnic Institute, Troy, NY
>>>         Website <https://sites.google.com/site/devendermaun/>
>>>
>>>
>>>
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>>
>>
>>
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>
>
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>
>
>
>
>     -- 
>     Devender
>     Graduate Student, Materials Science and Engineering
>     Rensselaer Polytechnic Institute, Troy, NY
>     Website <https://sites.google.com/site/devendermaun/>
>
>
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>     Ifeffit mailing list
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>
>
>
>
> -- 
> Christopher J. Patridge PhD.
> Contact: (315)-529-0501

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