Re: [Ifeffit] Ifeffit Digest, Vol 207, Issue 8

Dear Simon, good work Currently most synchrotron beamlines will report calibrations of the edge according to the inflection point, or first peak in the derivative spectrum. As we know, this changes with experimental resolution, monochromation pre-edge structure and bandwidth, so is neither a fixed definition nor fully portable. However, apart from direct [powder or single crystal] diffraction measurement post monochromation, this is one of the best markers we have to date. The discrepancy you mention is quite large prima facie to be just the above, so more likely is a calibration error or even monochromation calibration error [of one or the other]. These studies are very important to make progress in the field and to cross-calibrate, and to question theoretical predictions based around the edge structure, which are ongoing. [PS I did not directly answer your question!] Best wishes Chris -------------------------------------------------------------------------------------- Christopher Chantler, Professor, FAIP, Fellow American Physical Society Editor-in-Chief, Radiation Physics and Chemistry Chair, International IUCr Commission on XAFS; CIT, CCN IPP, International Radiation Physics Society School of Physics, University of Melbourne Parkville Victoria 3010 Australia +61-3-83445437 FAX +61-3-93474783 chantler@unimelb.edu.auhttps://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdAITgSrfUpfDAUV5oUH1LFYBcz08w8xvHMJoosZRdagfQM.&URL=mailto%3achantler%40unimelb.edu.au chantler@me.comhttps://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdAITgSrfUpfDAUV5oUH1LFYBcz08w8xvHMJoosZRdagfQM.&URL=mailto%3achantler%40me.com http://optics.ph.unimelb.edu.au/~chantler/xrayopt/xrayopt.htmlhttps://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdAITgSrfUpfDAUV5oUH1LFYBcz08w8xvHMJoosZRdagfQM.&URL=http%3a%2f%2foptics.ph.unimelb.edu.au%2f%7echantler%2fxrayopt%2fxrayopt.html http://optics.ph.unimelb.edu.au/~chantler/home.htmlhttps://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdAITgSrfUpfDAUV5oUH1LFYBcz08w8xvHMJoosZRdagfQM.&URL=http%3a%2f%2foptics.ph.unimelb.edu.au%2f%7echantler%2fhome.html ________________________________ From: Ifeffit on behalf of ifeffit-request@millenia.cars.aps.anl.gov Sent: Wednesday, 6 May 2020 8:14 AM To: ifeffit@millenia.cars.aps.anl.gov Subject: Ifeffit Digest, Vol 207, Issue 8 Send Ifeffit mailing list submissions to ifeffit@millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request@millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner@millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Reported W L3-edge and L2-edge energy (Bare, Simon R) ---------------------------------------------------------------------- Message: 1 Date: Tue, 5 May 2020 22:14:12 +0000 From: "Bare, Simon R" To: "ifeffit@millenia.cars.aps.anl.gov" Subject: [Ifeffit] Reported W L3-edge and L2-edge energy Message-ID: Content-Type: text/plain; charset="us-ascii" All: We are wondering if others agree that the reported values for the W L3 and W L2 edges are incorrect. We recently noticed the following: The "Edge" - defined by the inflection point of the absorption edge step When using the Ir L3 edge (11215.0 eV) as a calibration, the W L3- and L2-edges are 10203.4 eV and 11542.4 eV, respectively. When using the Pt L3 edge (11564.0 eV) as a calibration, the W L3- and L2-edges are 10203.3 eV and 11542.4 eV, respectively. These observations are thus different than the reported values of 10207.0 eV and 11544.0 eV for the L3 and L2 edges, respectively. Thanks in advance for the discussion and feedback. Simon R Bare Distinguished Scientist SSRL, MS69 SLAC National Accelerator Lab 2575 Sand Hill Road Menlo Park CA 94025 simon.bare@slac.stanford.edumailto:simon.bare@slac.stanford.edu Ph: 650-926-2629 [co_access_logo_text]