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

XAFS detection limit
by Christian Wittee Lopes 09 Feb '20

09 Feb '20

Dear all, Recently I was questioned about the EXAFS detection limit when describing different metal species in a bimetallic sample. By checking Pd and Cu K-edges, for example, I found Pd metal nanoparticles and CuO clusters, respectively. But additional techniques tell me I can have copper atoms in intimate contact with the Pd nanoparticles. What would be the minimum amount of these "single atoms" needed to be detected by EXAFS? is there a detection limit or it depends on several parameters? Thanks!!! -- *Christian Wittee Lopes* *Postdoctoral Researcher* Institute of Physics, Universidade Federal do Rio Grande do Sul (UFRGS) Phone: +55 54 992430264

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Re: [Ifeffit] Ifeffit Digest, Vol 204, Issue 1
by Christopher Chantler 07 Feb '20

07 Feb '20

Dear Christian and all I think we do not know yet, as the limits are getting better with improved techniques and error analysis, but it is a really good question. One can discuss limits from transmission versus fluorescence, in mM, in ppm; and separately perhaps in mass or mL or microL; or in e.g. atoms or molecules. I think every beamline has some guidelines, for their implementation. So yes it depends a lot on atomic number, density, need for a particular k range (e.g. XANES, normal XAFS, XERT etc.), beamline flux, and experimental method. Some of these estimates will be in the forthcoming International Tables for Crystallography, and earlier estimates are in earlier treatises. 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(a)unimelb.edu.au<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdA…> chantler(a)me.com<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdA…> http://optics.ph.unimelb.edu.au/~chantler/xrayopt/xrayopt.html<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdA…> http://optics.ph.unimelb.edu.au/~chantler/home.html<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdA…> ________________________________ From: Ifeffit <ifeffit-bounces(a)millenia.cars.aps.anl.gov> on behalf of ifeffit-request(a)millenia.cars.aps.anl.gov <ifeffit-request(a)millenia.cars.aps.anl.gov> Sent: Saturday, 8 February 2020 5:00 AM To: ifeffit(a)millenia.cars.aps.anl.gov <ifeffit(a)millenia.cars.aps.anl.gov> Subject: Ifeffit Digest, Vol 204, Issue 1 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. XAFS detection limit (Christian Wittee Lopes) ---------------------------------------------------------------------- Message: 1 Date: Thu, 6 Feb 2020 23:39:13 -0300 From: Christian Wittee Lopes <chriswittee(a)gmail.com> To: Ifeffit(a)millenia.cars.aps.anl.gov Subject: [Ifeffit] XAFS detection limit Message-ID: <CAJHLRaEz1SJ8dsA+WySAq4Uc2JR=cHApDQ+yZ+yHguqELU+tOw(a)mail.gmail.com> Content-Type: text/plain; charset="utf-8" Dear all, Recently I was questioned about the EXAFS detection limit when describing different metal species in a bimetallic sample. By checking Pd and Cu K-edges, for example, I found Pd metal nanoparticles and CuO clusters, respectively. But additional techniques tell me I can have copper atoms in intimate contact with the Pd nanoparticles. What would be the minimum amount of these "single atoms" needed to be detected by EXAFS? is there a detection limit or it depends on several parameters? Thanks!!! -- *Christian Wittee Lopes* *Postdoctoral Researcher* Institute of Physics, Universidade Federal do Rio Grande do Sul (UFRGS) Phone: +55 54 992430264

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XAFS.ORG WEBSITE??
by Bare, Simon R 30 Jan '20

30 Jan '20

Talking of websites does anyone know what happened to the International XAFS website? I can't access it. And what is going on with this organization? Thanks. Simon

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what happened to the website?
by Matthew Marcus 30 Jan '20

30 Jan '20

The http://millenia.cars.aps.anl.gov/ website seems to have gone off-line, which means that WebAtoms doesn't work anymore. Is there a replacement? Of course, I can use the stand-alone Atoms in Demeter. -- Sincerely, Matthew Marcus

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color of fonts in demeter
by Ricardo Faccio 29 Jan '20

29 Jan '20

Dear all After installing Demeter in MacOS I am having some problems related to the color of fonts and background. Since they look identical is diffcult to see and read. How could be possible to change the color of fonts? I am attaching an example. Best regards Ricardo -- ------------------------------------------------------------------------- Dr. Ricardo Faccio Prof. Agregado de Física (Assoc. Prof.) Mail: Área Física, DETEMA, Facultad de Química, Universidad de la República Av. Gral. Flores 2124, C.C. 1157 C.P. 11800, Montevideo, Uruguay. E-mail: rfaccio(a)fq.edu.uy Phone: (+598) 2924 9859 (+598) 2929 0648 Fax: (+598) 2924 1906 Web: http://cryssmat.fq.edu.uy/ricardo/ricardo.htm

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Fw: Re: request help about Zn standard spectra
by Qiang Chang 27 Jan '20

27 Jan '20

Dear Mauro, Thank you so much for your kind and quick help. Best reards, Qiang From: Mauro Rovezzi Date: 2020-01-27 09:45 To: ifeffit Subject: Re: [Ifeffit] request help about Zn standard spectra Dear Qiang, Here some Zn K-edge spectra from the SSHADE/FAME database: https://www.sshade.eu/search?db=fame&query=%22Zn%20K%20edge%22 Best regards, Mauro On 2020-01-26 21:06, Qiang Chang wrote: > Hi all, > > May I ask if you have some standard spectra for Zn elements, like > metallic Zn, ZnO, ZnNx, etc. I am vey appreciative if you could send me > some copies. > > Thank you very much. > > Best regards, > Qiang > > _______________________________________________ > Ifeffit mailing list > Ifeffit(a)millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit > _______________________________________________ Ifeffit mailing list Ifeffit(a)millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

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request help about Zn standard spectra
by Qiang Chang 27 Jan '20

27 Jan '20

Hi all, May I ask if you have some standard spectra for Zn elements, like metallic Zn, ZnO, ZnNx, etc. I am vey appreciative if you could send me some copies. Thank you very much. Best regards, Qiang

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interesting job posting at NSLS-II
by Ravel, Bruce 26 Jan '20

26 Jan '20

Hi all, A colleague of mine here at NSLS-II has an interesting post-doc position open right now. https://jobs.bnl.gov/job/upton/postdoctoral-research-associate-in-total-sca… This position is for a person doing total scattering (aka PDF). Strictly speaking, not an XAS position, but perhaps of interest to someone with an XAS background who is looking for a post-doc. Regards, Bruce -- Bruce Ravel ------------------------------------ bravel(a)bnl.gov National Institute of Standards and Technology Synchrotron Science Group at NSLS-II Lead Beamline Scientist, 6BM (BMM) Building 743, Room 114 Upton NY, 11973 Homepage: http://bruceravel.github.io/home/ Beamline: https://www.bnl.gov/ps/beamlines/beamline.php?r=6-BM Software: https://github.com/bruceravel Demeter: http://bruceravel.github.io/demeter/

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smoothing XAS data
by Daria Boglaienko 23 Jan '20

23 Jan '20

Hello, In what case smoothing of the data is OK? My data have a lot of noise and smoothing really helps (visually). I compared fit done in Artemis for smoothed and non-smoothed data sets and the result is very similar, however when I searched about it online, it looks like it is not recommended. What is a good way to justify it? Thank you! -Daria

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Re: [Ifeffit] Ifeffit Digest, Vol 203, Issue 5
by Christopher Chantler 23 Jan '20

23 Jan '20

Dear all I agree with Mike and Scott too. I might suggest Schalken, M. J. and Chantler, C. T. "Preservation of uncertainty in experiment: structures of Ni (II) coordination complexes" (2018) J. Synchrotron Rad., 25, 920-934 as a partial discussion around this topic if people are interested. It could be read as 'don't smooth data if you can avoid it'. Very best wishes to all 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(a)unimelb.edu.au<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdA…> chantler(a)me.com<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdA…> http://optics.ph.unimelb.edu.au/~chantler/xrayopt/xrayopt.html<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdA…> http://optics.ph.unimelb.edu.au/~chantler/home.html<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdA…> ________________________________ From: Ifeffit <ifeffit-bounces(a)millenia.cars.aps.anl.gov> on behalf of ifeffit-request(a)millenia.cars.aps.anl.gov <ifeffit-request(a)millenia.cars.aps.anl.gov> Sent: Thursday, 23 January 2020 4:05 PM To: ifeffit(a)millenia.cars.aps.anl.gov <ifeffit(a)millenia.cars.aps.anl.gov> Subject: Ifeffit Digest, Vol 203, Issue 5 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. smoothing XAS data (Daria Boglaienko) 2. Re: smoothing XAS data (Carlo Segre) 3. Re: smoothing XAS data (Scott Calvin) 4. Re: smoothing XAS data (Mike Massey) 5. Re: smoothing XAS data (Will Bennett) ---------------------------------------------------------------------- Message: 1 Date: Wed, 22 Jan 2020 17:38:43 -0800 From: Daria Boglaienko <dbogl003(a)fiu.edu> To: ifeffit(a)millenia.cars.aps.anl.gov Subject: [Ifeffit] smoothing XAS data Message-ID: <CAACWq8BmJFr0QNUHk1YrsB7w3BLGhzyus9pXow0Ng+ER3eAZDQ(a)mail.gmail.com> Content-Type: text/plain; charset="utf-8" Hello, In what case smoothing of the data is OK? My data have a lot of noise and smoothing really helps (visually). I compared fit done in Artemis for smoothed and non-smoothed data sets and the result is very similar, however when I searched about it online, it looks like it is not recommended. What is a good way to justify it? Thank you! -Daria

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