- Ifeffit - millenia.cars.aps.anl.gov

HELP
by Diego Fernando 27 Jun '12

27 Jun '12

For some time I'm using FEFF8.4 for calculations of absorption-XANES and DOS in some superconducting materials for which it has been successful, now I have the need to include in the'' input "of some impurity atoms in interstitial positions by Example: *A* *1.16* *B* where *A* and *B* are two different species of atoms, I made several attempts in trying to implement this using ATOMS3.0 on the web: http://millenia.cars.aps.anl.gov/cgi-bin/atoms/atoms.cgi but I have not had consistent results, in ATOMS3.0 manual explains that the program has been designed for this, but suggests that it may be possible. I appeal to you to see if I can help solve this problem. Thanks for your attention. Diego Fernando Mulato Gómez. Estudiante de doctorado en Física Teórica, CINVESTAV, Unidad Mérida, México.

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Problem occurs in ARTEMIS
by Ashok Yadav 27 Jun '12

27 Jun '12

Dear All, I am using windows 7 professional in my desktop. My ARTEMIS (0.8.014 free available) is not working properly even Athena is working very well. When I am opening my project files which is fitted and saved day before, artemis is not opening it and showing an error massage "Artemis trapped one or more errors! Error message dumped to the screen" , but I couldn't see such error message on the screen. This same massage is also occurring when I try to quit from Artemis window and it isn't quitting. When I opened this project files using artemis installed in another PC and my laptop these project files are working very well (even I can refine fitting in another PC using same artemis version). I have re installed the software but the same problem occurs again and again. If anyone encountered problem like this please help me to resolve it. Thank you Ashok

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Histograms with Demeter -- meaning of fit values
by Walter Fu 25 Jun '12

25 Jun '12

Hi all, I'm trying to do a preliminary fit to the first shell of an amorphous material, using a histogram generated from diffraction data. I've been using a script similar to the one given here: http://bruceravel.github.com/demeter/dpg/examples/histo.html When I run my script, it creates an SS path for each histogram bin and then performs the fit, as expected. However, if I then query the fit object for a summary, I get a list of fitted values back. My question is, what is the meaning of these values? Do they refer to the fit as a whole, or individual paths within the fit? For instance, is the "delR" value the one which, when applied uniformly to all of the paths generated, produces the best fit? Or is it merely the value calculated for the last-used path (presumably the one corresponding to last bin in the histogram), which may be different for the second-to-last path or for the first path? I'm also a bit confused as to how the "amp" variable (line 30 in the script from the link given above) comes into play. Is the reported value a single multiplicative factor which is applied to the histogram-generated amplitudes of all the paths, or is there a separate "amp" for each path, with only the one corresponding to the last-accessed path being reported? I've tried looking through the Demeter source to get the answers, but given my limited knowledge of Perl, my search is proving less than conclusive. Any explanations you could give would be greatly appreciated. -Walter

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PCA component determination
by Santiago José Alejandro Figueroa 23 Jun '12

23 Jun '12

Dear all, Determine the number of components in Principal Component Analysis decomposition is usually a hard work, close to an art. Recently Malinowski discuss some methods in a paper that is proposed a new method (DRMAD): DOI: 10.1002/cem.1182 This last method has in the program developed by Carmelo Prestipino PCA_GUI.py (http://code.google.com/p/prestopronto/) developed with some advices of Marcos Fernandez-Garcia. There are many methods better than use the empirical IND funtion. The better is have a good knowledge of your system by other techniques or by the behavior, this additional information can be of the extreme importance if you have more than 2 components. Best regards, Santiago -------------------------------------------- Dr. Santiago J. A. Figueroa Pesquisador - Laboratório Nacional de Luz Síncrotron (LNLS) Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) Rua Giuseppe Máximo Scolfaro, 10000 Caixa Postal 6192 - CEP 13083-970, Campinas(SP), BRASIL Tels.: (sala)19 3517-5063 / (xafs2)19 3512-1246 / (xafs1)1139 / (dxas)1141 Fax: 19 3512-1006 WEB: http://www.lnls.br BLOG: http://www.marevero.blogspot.com/

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Re: [Ifeffit] on Tune and Detune
by Enyuan Hu 22 Jun '12

22 Jun '12

Dear Matthew, Thank you so much for the answer. It's crystal clear :) Enyuan

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on Tune and Detune
by Enyuan Hu 21 Jun '12

21 Jun '12

Dear all, I'm new to the community and I was wondering if I can ask some basic questions here. I heard the beamline scientist mention "tune" and "detune" and I saw in some materials say "detune to get rid of high order harmonics", but what is "harmonics"? and why it's necessary to detune to get rid of high order harmonics? I'd really appreciate it if we can discuss this a little bit. Thanks. Enyuan

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Sixpack, PCA controll, "IND" column
by Joerg Goettlicher 21 Jun '12

21 Jun '12

Hello, does anyone know the meaning of the IND column in the PCA controll field of sixpack (version 0.63)? I did not found a hint in the sixpack documentation. Best regards Joerg

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Re: [Ifeffit] Horae examples with Mac distribution
by Scott Calvin 16 Jun '12

16 Jun '12

On Thursday, June 14, 2012 04:09:30 PM Bruce Ravel wrote: For the old software, look here: http://cars9.uchicago.edu/svn/horae/trunk/examples/ For the new software, look here: https://github.com/bruceravel/demeter/tree/master/examples or simply clone demeter from github. Then you'll get all the source along with the examples. I also keep a mountain of example data (much of which is in all three places) here: https://github.com/bruceravel/XAS-Education/tree/master/Examples Those are all the data used in my various XAS training lectures. Thanks, Bruce! The example data from your lectures is particularly helpful to know about. --Scott Calvin Sarah Lawrence College

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Horae examples with Mac distribution
by Scott Calvin 14 Jun '12

14 Jun '12

Hi all, When I download the universal binary of Ifeffit (1.2.12) and Horae for Mac, it doesn't seem to include the folder of example files--or at least I can't find the files with a search. Are they actually there somewhere? If not, is there a way to download just those files? I've got a copy of them from past distributions, and I've now sent a copy of them to my student, so we're actually set. Still, I thought it worth asking on behalf of other Mac users. --Scott Calvin Sarah Lawrence College

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Another brain teaser
by Anatoly I Frenkel 13 Jun '12

13 Jun '12

Here is another brain teaser in case anyone is bored. The solution was not at all obvious but very simple, as all brain teaser solutions should be. Anatoly

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