September 2023 - Ifeffit - millenia.cars.aps.anl.gov

TiOx K-edge spectra
by Rebecca Katharina Pittkowski 20 Sep '23

20 Sep '23

Dear community, I am preparing a teaching exercise for a course on nano-structure characterization, and I was hoping that someone has some K-edge spectra of titanium oxide nanoparticles lying around that I could reuse for the course. I have been through the NIMS Material Data Repository and found some useful references but it would be great to have a nano-sized example as well. That could very well be from a published article, which I could include in the teaching. Thanks for any input. Greetings from Copenhagen, Rebecca Rebecca K. Pittkowski Tenure-track Assistant Professor University of Copenhagen Center for High Entropy Alloy Catalysis Department of Chemistry Universitetsparken 5 2100 Copenhagen Ø DENMARK Rebecca.pittkowski(a)chem.ku.dk [/var/folders/gc/lhyz4xy96q77x4sbrrh4l46r0000gn/T/com.microsoft.Outlook/WebArchiveCopyPasteTempFiles/cidimage009.png(a)01D5C49F.F68E4220]

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P K-edge EXAFS
by Marcelo Eduardo Alves 15 Sep '23

15 Sep '23

Hi there, I begin by examining phosphorus adsorption by goethite, hematite, and gibbsite. Why is it difficult, if not impossible, to obtain EXAFS spectra at the P-K edge that can be properly used, i.e., spectra with a high signal-to-noise ratio, especially for dilute samples? Would it be possible to use arsenic as a phosphorus proxy to get conclusions from As K-edge EXAFS data that could be extended to P? Thank you.

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EXAFS-50 symposium and short course, Oct. 30-Nov. 3 at BNL
by Anatoly Frenkel 08 Sep '23

08 Sep '23

Dear subscribers: Sharing here my Linkedin post: I am excited to share that Brookhaven National Laboratory will be hosting the Symposium ("EXAFS-50") that will mark the 50th anniversary of Stern-Sayers-Lytle team's introduction of the Extended X-ray Absorption Fine Structure (EXAFS) technique in early 1970s. The Symposium will open the week of events, hosted by Brookhaven National Laboratory, that will include the talks of the experts in the field on the past, present and future of the EXAFS technique on Oct. 30 and 31, and culminate by the three-day long short course on advanced data analysis methods of EXAFS, from Nov. 1 to 3. Both events will be in-person. The web sites below have all the information for registration for the symposium (registration begins on Aug. 21) and for application/registration for the short course (application deadline is Aug. 31). Although the Symposium and the Short course are organized and run as separate events, attending both of them will be ideal for graduate students and postdocs. No registration fee is charged for attending these events but registration is required. EXAFS-50: https://www.bnl.gov/exafs-50/ XAFS short course: https://www.bnl.gov/xafscourse/ ------------------------------------------------------------------- Anatoly I. Frenkel Professor Department of Materials Science and Chemical Engineering (primary appointment) Department of Chemistry (affiliate appointment) * 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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CatMASS - XAS "Catalyst" Sample Mass Calculator
by Hoffman, Adam S 07 Sep '23

07 Sep '23

Hi All, We would like to announce the release of CatMASS - a XAS (and X-ray scattering) sample mass calculator for complex sample compositions most commonly found in catalysis science. This software builds off of codes found in Hephaestus and XAFSMass allowing for more complex sample descriptors (multiple metals/supported organometallics) and allows for the inclusion of diluents. The absorption can be visualized in E- or k-space highlighting potentially competing edges in the sample that may limit the range of your EXAFS data collection. The documentation can be found in the recent publication: https://onlinelibrary.wiley.com/iucr/doi/10.1107/S160057752300615X To download the executable file (windows only) please see the link here: https://web.slac.stanford.edu/coaccess/resources/software To download the python-based version or collaborate on the GitHub project please go to: https://github.com/ahoffm02/catMass If you have any questions please reach out to Jorge Perez-Aguilar (jperezag(a)slac.stanford.edu<mailto:jperezag@slac.stanford.edu>) or myself, Adam Hoffman (ashoff(a)slac.stanford.edu<mailto:ashoff@slac.stanford.edu>). Cheers, Adam Hoffman, Jorge Perez-Aguilar, and the Co-ACCESS team

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Shift in Eo when fitting PtO2 and similar samples
by Zi Qi Chen 07 Sep '23

07 Sep '23

Dear all, I am looking at EXAFS of PtO2 powders and Pt particles supported on TiO2. I used a beta-PtO2 crystal structure data for the PtO2 EXAFS and after the first shell fit, I observed a large shift in Eo (delta Eo of ~14 eV) in my fit parameters. When I tried to fit the Pt foil to obtain the So2, the energy shift also seemed high (delta Eo of ~7 eV). I am wondering if there could be a problem in the selection of Eo prior to EXAFS analysis? I left the Eo as the energy at the first peak of first derivative (ifeffit default). All of the data were also aligned using the reference foil in Athena before looking at EXAFS. I am wondering what would have caused this shift? Any help is appreciated, thank you. Best regards, Yanny

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