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XAFS fitting in xas_viewer and reset of customized variables after save & load cycle
by juejing.liu＠gmail.com 04 Sep '22

04 Sep '22

Hi all, I am using xas_viewer, version 0.9.65, to fit some XAFS data. In a typical situation I will also fit the coordination numbers of atoms by add customized variables in the amplitude boxes (image below). It works fine during my fitting. However, when I save my result as a larch session and load it later, all my customized parameters are disappeared, and the amplitude boxes are reset. Therefore, I need to refill all the variables after each save & load cycle. This becomes increasingly tedious when dealing with about 20 different paths. Is there any workaround of this problem? Best, Juejing Liu Guo Group Materials Science and Engineering program Alexandra Navrotsky Institute for Experimental Thermodynamics Washington State University Pullman, WA 99164-4630 Office: Fulmer Hall, Room 630 Phone: 208-206-7304

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Simultaneous multispectral fitting in Larch?
by Van Stappen, Casey M 30 Aug '22

30 Aug '22

To whom it concerns, I wanted to inquire regarding how best to perform multispectral fitting (i.e. fitting several EXAFS spectra simultaneously with shared parameters) in Larch? This was something that could be done with (relative) ease in Artemis, but I was hoping to perform this at a larger scale (6 spectra, >10 restrictions) in Larch. I’ve hunted through Dr. Newville’s excellent Youtube tutorials, but didn’t find this specific information. Thank you for your help! Best, Casey Van Stappen ------------------------------------------------------------------------ Dr. Casey Van Stappen University of Texas at Austin Robert A. Welch Hall, 4.318 2350 Speedway Austin, TX 78705 USA Phone: +1 (512) 775-2658 E-mail: casey.vanstappen(a)austin.utexas.edu

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XAFS short course at BNL: November 2-4
by Anatoly Frenkel 29 Aug '22

29 Aug '22

Dear subscribers, This is a reminder about the annual XAFS short course at BNL. The dates are: November 2-4. It will be virtual. The level will be intermediate to advanced As in the past, lectures, discussions and software demonstration sessions will be on Wednesday and Thursday, and the full day data analysis practicum will be on Friday. The course agenda and the link to the application form are available at the BNL web site: https://www.bnl.gov/xafscourse/index.php and at the web site of the Synchrotron Catalysis Consortium: https://you.stonybrook.edu/scc2/xafs-workshops/ Registration deadline is September 11. Regards, Anatoly ------------------------------------------------------------------- Anatoly I. Frenkel Professor Department of Materials Science and Chemical Engineering Stony Brook University Stony Brook, NY 11794 Email: anatoly.frenkel(a)stonybrook.edu <https://mail.bnl.gov/OWA/redir.aspx?C=F6wCGt4adziN6IvpdRQ-rWdgy3Oaoif_x-0yb…> http://you.stonybrook.edu/frenkel Co-Director and Spokesperson, Synchrotron Catalysis Consortium (SCC) at BNL http://you.stonybrook.edu/scc2 Joint Appointment: Senior Chemist Chemistry Division, Brookhaven National Laboratory Upton, NY 11973. Ph: 631-344-3013. Group: 631-344-3494 Email: frenkel(a)bnl.gov https://www.bnl.gov/staff/frenkel -------------------------------------------------------------------

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Question related to an example of EXAFS fitting using Larch
by Andy Zhang 29 Aug '22

29 Aug '22

Dear all, I am learning Larch and read the manual of Larch online. In the "13.8.10. Example 3: Fit 3 datasets with 1 Path" of the webpage https://xraypy.github.io/xraylarch/xafs_feffit.html#example-3-fit-3-dataset…, it shows an example that fitting Cu at different temperatures. Einstein model was used to simulate the sigma2, as shown in the figure below. [image: image.png] However, in some papers (eg. Radiation Physicsand Chemistry137 (2017) 93–98) that model EXAFS at elevated temperatures, they separates the total sigma2 to static and thermo components (Sigma^2 = Sigma_static^2 + Sigma_thermo^2), which is different from the above Larch example. I am a little confused about the utilization of Einstein model. I wonder if the Sigma2 obtained by Einstein model can reflect the total sigma2 or can only reflect the thermo part. Many thanks for your help! Best regards, Harry

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Re: [Ifeffit] XAFS fitting in xas_viewer and reset of customized
by juejing.liu＠gmail.com 28 Aug '22

28 Aug '22

Hi Matt, Here is the session file for the UO2 fitting. The screenshot blow shows what the customized variables look like right before saving this session. Please feel free to let me know if you need any extra information. Best, Juejing Liu Guo Group Materials Science and Engineering program Alexandra Navrotsky Institute for Experimental Thermodynamics Washington State University Pullman, WA 99164-4630 Office: Fulmer Hall, Room 630 Phone: 208-206-7304

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Re: [Ifeffit] XAFS fitting in xas_viewer and reset of customized variables after save & load cycle
by Liu, Juejing 28 Aug '22

28 Aug '22

Hi Matt, Thanks for the quick response. I just noticed that the data in the screenshot is unpublished data so I may not be able to send you that one. But I will send you a typical UO2 fitting later today (in the larch session) so that you can look. Best, Juejing Liu Guo Group Materials Science and Engineering program Alexandra Navrotsky Institute for Experimental Thermodynamics Washington State University Pullman, WA 99164-4630 Office: Fulmer Hall, Room 630 Phone: 208-206-7304

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Quick Absorption and Scattering (QAS) beamline scientist position at NSLS II
by Stavitski, Eli 26 Aug '22

26 Aug '22

Dear all, We are looking for a beamline scientist for Quick Absorption and Scattering (QAS) beamline (https://www.bnl.gov/nsls2/beamlines/beamline.php?r=7-BM) The full job description is available here https://jobs.bnl.gov/job/upton/beamline-scientist-quick-x-ray-absorption-an… ____________________________________ Eli Stavitski, PhD, Physicist Inner Shell Spectroscopy (ISS) Lead Beamline Scientist National Synchrotron Light Source-II Bldg. 743, Brookhaven National Laboratory Upton, NY 11973-5000 631 344 8641 istavitski(a)bnl.gov<mailto:istavitski@bnl.gov> https://www.bnl.gov/ps/beamlines/beamline.php?r=8-ID

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third cumulant in Larch
by Andy Zhang 19 Aug '22

19 Aug '22

Dear all, I have a quick question related to EXAFS fitting using Larch. I wonder how to include the third cumulant in the fitting. I tried to add "third" in the "pars" section, but it seems it did not work. [image: image.png] Thanks a lot for your help! Have a nice day! Best, Harry

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Environmental geochemist position at DOE-National Energy Technology Laboratory
by Mengling Stuckman 18 Aug '22

18 Aug '22

Dear ifeffit members, Recently we are interested in hiring an environmental geochemist for our critical mineral sustainability program at NETL, Pittsburgh, PA. Synchrotron experience is a plus. U.S. citizens are strongly preferred. Here is the specific job posting. https://leidos.wd5.myworkdayjobs.com/External/job/Pittsburgh-PA/Environment… Feel free to pass along this information to your students who are interested. If you have any questions related to the post, feel free to contact me at mengling.stuckman(a)netl.doe.gov Thanks and have a nice day, Mengling -- Mengling Stuckman Leidos Technical Fellow National Energy Technology Laboratory U.S. Department of Energy Pittsburgh, PA mengling.stuckman(a)netl.doe.gov Office: 412-386-7387

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Using larch for feff Fitting -> simple 4 parameter fit
by Mangold, Stefan (IPS) 18 Aug '22

18 Aug '22

Dear all, I try to use larch for Feff Fitting. For a first start, I liked the option of Artemis with the „simple 4 parameter fit“. Larch produces for every path an independent dear and sigma2. Is there a simple way to make this simple 4 parameter fit also in larch? best regards Stefan Mangold

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