Re: [Ifeffit] Error in second shell fit

Well that is interesting, As was asked earlier, what is the fitted reff from the model? It would be rather non-physical and probably suggest a poor model, but perhaps the bond length is shifted well beyond the rmax which you show sets as 7 A and that is why you are receiving the error. Chris ******************************** Christopher J. Patridge, PhD NRC Post Doctoral Research Associate Naval Research Laboratory Washington, DC 20375 Cell: 315-529-0501 On 2/20/2013 1:11 PM, Devender wrote:

Bruce and Chris,

Thanks for follow-up. I understand the frustration on your part.

Reason for doubt is I am doing exactly the same thing Chris suggested even before posting the question here i.e. changing the rmax. I have changed rmax to even 9 A whereas shell I am trying to fit is only 5 A (please see attached screenshot) but still getting error log that reff is larger than rmax. I know by default it is set to 3 A but I have tried to change it values more then reff of path but still getting the same error. Please see attached screenshot where rmax I am using is 7 A where as Reff is only around 5 A but still getting the error log.

Regards, Dev

On Wed, Feb 20, 2013 at 12:49 PM, Bruce Ravel mailto:bravel@bnl.gov> wrote:

On Wednesday, February 20, 2013 10:54:02 AM Devender 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

Dev,

I get the impression from your emails that you have not much availed yourself of the resources that are already available for learning how to use the software.

At http://bruceravel.github.com/demeter/ you will find the Artemis manual. I'll admit, it's still pretty mediocre, but it's a start. You will also find some videos that go a long way towards explaining how the software works.

You may find it useful to spend some time with those things. I certainly think some time spent with those resrouces would obviate a problem like "I am not sure if I ... completely ... understand the difference of Rmax in artemis and feff." That, frankly, isn't a very good question. While it is certainly true that Artemis suffers from being a program written by a physicist who has no training in computer science, user experience engineering, or design, you would have found the answer to that question even in the fairly crappy Artemis manual.

B

--

Bruce Ravel ------------------------------------ bravel@bnl.gov mailto:bravel@bnl.gov

National Institute of Standards and Technology Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2 Building 535A Upton NY, 11973

Homepage: http://xafs.org/BruceRavel Software: https://github.com/bruceravel _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov mailto:Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit

-- Devender Graduate Student, Materials Science and Engineering Rensselaer Polytechnic Institute, Troy, NY Website https://sites.google.com/site/devendermaun/

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