May 2022 - Ifeffit - millenia.cars.aps.anl.gov

1. structure for reference Mn foil (Hu, Yang (HIU))
by Pierre Lecante 13 May '22

13 May '22

Dear Yang Hu, Your experience rings à bell in my mind: several times we got weird data from Co and Fe NPs, with S02 close to 0.2, much smaller than expected for a simple size effect. The point is that PDF studies were consistent with the so called Co Epsilon structure... based on the Mn beta phase, very disordered. By the way, I'd be very interested to check hypothesis on my side : I'd be very glad if you could provide me à data set. Sincerely, Pierre Lecante Le 13 mai 2022 19:00:01 GMT+02:00, ifeffit-request(a)millenia.cars.aps.anl.gov a écrit : >Send Ifeffit mailing list submissions to > ifeffit(a)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(a)millenia.cars.aps.anl.gov > >You can reach the person managing the list at > ifeffit-owner(a)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. structure for reference Mn foil (Hu, Yang (HIU)) > > >---------------------------------------------------------------------- > >Message: 1 >Date: Thu, 12 May 2022 18:29:19 +0000 >From: "Hu, Yang (HIU)" <yang.hu(a)kit.edu> >To: "Ifeffit(a)millenia.cars.aps.anl.gov" > <Ifeffit(a)millenia.cars.aps.anl.gov> >Subject: [Ifeffit] structure for reference Mn foil >Message-ID: <999901d0ad3743f59182feca823a08bd(a)kit.edu> >Content-Type: text/plain; charset="us-ascii" > >Dear IFEFFIT members, > > > >I have been trying to obtain the S02 value from metal reference foils >measured at the beamline. > > > >However, I constantly got a very low S02 value, such as 0.2 or 0.3 using Mn >alpha or gamma cif file (first shell of 12 Mn). Only Mn-beta (4 subshell * 3 >Mn) could give a S02 in the range 0.8 ~ 1, depending on whether I >constrained sigam2 for all the 12 Mn or whether I fixed the CN for each >subshell. But the uncertainty is very high. > > > >I also fitted the MnO measured together leaving S02 variable, and it >resulted in a S02 close to 1. So I am guessing I didn't use the correct >structure file for Mn foil . > > > >I appreciate if someone could help on this! > > > >Best regards, > >Yang Hu > > > > > >

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Larch 0.9.59, problems with PCA
by Mangold, Stefan (IPS) 10 May '22

10 May '22

Dear all, on 2 computers (Mac, Intel and ARM, newest version operating system) the PCA does not work. If I press "Build Model with selected groups“ on both computers and several different datasets, I only get „training model“ and nothing else happens. Absolutely nothing else changes within this tab inside XAS viewer. Best regards Stefan Mangold

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Question about an EXAFS analysis of C60-Cu/SiO2
by 王茂林 06 May '22

06 May '22

Dear IFEFFIT members, Recently I have read a paper <ambient-pressure synthesis of ethylene glycol catalyzed by C60-buffered Cu/SiO2> (https://www.science.org/doi/10.1126/science.abm9257) I have a question about the EXAFS analysis: the wavelet transform of C60-Cu/SiO2 (Figure S15B) has 2 peaks at (k, R) = (1.4, 2.2) and (3.8, 1.5), the author assigned them to Cu-C and Cu-O, respectively. And they think Cu-C is derived from d-\pi interactions between Cu and C60. However, Cu-C and Cu-O paths can hardly be separated since the f(k) and \phi(k) are nearly identical for C and O. Besides, the Cu-C distance is ~2 angstrom (according to the ref. 30: S.-Z. Zhan et al., J. Am. Chem. Soc. 2020, 142, 5943-5947.), why it can have a peak at R = 2.2 angstrom? (with Cu-O R = 1.5 angstrom) Thanks you advance for you time! Best regards, Maolin Wang

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