Julian: I agree with Anatoly. The amplitude of the EXAFS is quite large. I have seen a similar effect in metal foils and NP samples when you forget to take the log of the I0 and IT. This also forces the S02 factor to be artificially high (like it is for your samples) when fitting in Artemis. Maybe try to re-adjust the raw data file upon importing into Athena and then see if your spectra (intensities, features and S02) line up better with those from the literature (and from the very useful Lytle database on XAFS.org). Hope that helps Dave
On Fri, Oct 14, 2011 at 9:14 AM, <ifeffit-requ...@millenia.cars.aps.anl.gov>wrote: > 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-requ...@millenia.cars.aps.anl.gov > > You can reach the person managing the list at > ifeffit-ow...@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. Re: Gold Nanoparticle first shell fitting (Kaiser, Julian) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 14 Oct 2011 14:14:00 +0000 > From: "Kaiser, Julian" <julian.kai...@helmholtz-berlin.de> > To: XAFS Analysis using Ifeffit <ifeffit@millenia.cars.aps.anl.gov> > Subject: Re: [Ifeffit] Gold Nanoparticle first shell fitting > Message-ID: <DE491AE4BEF1864DB8831D1BC0E7EA1A0E554D33@didag2> > Content-Type: text/plain; charset="iso-8859-1" > > Dear Anatoly, > > thanks a lot for your reply! > I don't see the problem yet. In the attached file > ("different_Au_foils.prj), there are two different gold reference foils > measured at two different synchrotrons. There is some difference but not > realy much. Could you please describe the regions that are worse comparing > my gold foil-file to yours, or if possible, attache the file with both foils > or at least a screenshot of the plot? > > Best regards, > Julian > > > > ________________________________ > Von: ifeffit-boun...@millenia.cars.aps.anl.gov [ > ifeffit-boun...@millenia.cars.aps.anl.gov]" im Auftrag von "Anatoly I > Frenkel [afren...@yu.edu] > Gesendet: Dienstag, 11. Oktober 2011 20:29 > Bis: XAFS Analysis using Ifeffit > Betreff: Re: [Ifeffit] Gold Nanoparticle first shell fitting > > > Something is horribly wrong with the data here. > > I overplotted your reference Au foil against mine, and yours has distorted > XANES and too high EXAFS intensity compared to my data. Your amplitude > factor is 1.54 which also confirms that something was wrong in the > experiment. Perhaps - a misalignment? The NP data also look strange... > > I would not focus on the NP analysis until you figure out why your foil > data is so strange. > > > > > > ________________________________ > From: ifeffit-boun...@millenia.cars.aps.anl.gov [ > ifeffit-boun...@millenia.cars.aps.anl.gov] on behalf of Kaiser, Julian [ > julian.kai...@helmholtz-berlin.de] > Sent: Tuesday, October 11, 2011 1:06 PM > To: ifeffit@millenia.cars.aps.anl.gov > Subject: [Ifeffit] Gold Nanoparticle first shell fitting > > Dear Ifeffit Community, > > I'm trying to fit a gold nanoparticle in the size of about 2 nm that is > immobilized by polymers. For my research it's enought to fit the first shell > only, becaues all I would like to analyze is the atomic distance in the > nanoparticle. After the (hopefully) correct background substraction in > Athena (athena file attached), there is a shoulder at approx. 2.1 Angstr?m > in the R-space. > In Artemis, fitting this shoulder seems not to be possible, while the fit > for the reference (gold foil) seems to be fine. (both artemis files are > attached to the e-mail). > If the k-range is decreased from 12.388 to a value between 9 an 10, the > shoulder disappears and the fit works fine. But I think by this change I > might modify the data too much. > Would be really nice, if sombody has an idea how to deal with the problem, > to get a hint how to solve this. > > Thanks a lot, > Julian > > ________________________________ > > Helmholtz-Zentrum Berlin f?r Materialien und Energie GmbH > > Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren > e.V. > > Aufsichtsrat: Vorsitzender Prof. Dr. Dr. h.c. mult. Joachim Treusch, stv. > Vorsitzende Dr. Beatrix Vierkorn-Rudolph > Gesch?ftsf?hrer: Prof. Dr. Anke Rita Kaysser-Pyzalla, Dr. Ulrich Breuer > > Sitz Berlin, AG Charlottenburg, 89 HRB 5583 > > Postadresse: > Hahn-Meitner-Platz 1 > D-14109 Berlin > > http://www.helmholtz-berlin.de > > ________________________________ > > Helmholtz-Zentrum Berlin f?r Materialien und Energie GmbH > > Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren > e.V. > > Aufsichtsrat: Vorsitzender Prof. Dr. Dr. h.c. mult. Joachim Treusch, stv. > Vorsitzende Dr. Beatrix Vierkorn-Rudolph > Gesch?ftsf?hrer: Prof. Dr. Anke Rita Kaysser-Pyzalla, Dr. Ulrich Breuer > > Sitz Berlin, AG Charlottenburg, 89 HRB 5583 > > Postadresse: > Hahn-Meitner-Platz 1 > D-14109 Berlin > > http://www.helmholtz-berlin.de > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20111014/54d44612/attachment.htm > > > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: different_Au_foils.prj > Type: application/octet-stream > Size: 22176 bytes > Desc: different_Au_foils.prj > URL: < > http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20111014/54d44612/attachment.obj > > > > ------------------------------ > > _______________________________________________ > Ifeffit mailing list > Ifeffit@millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > > > End of Ifeffit Digest, Vol 104, Issue 22 > **************************************** > -- ********************************** David Sprouster Postdoctoral Research Fellow Department of Electronic Materials Engineering Research School of Physics and Engineering The Australian National University Canberra ACT 0200 Australia Currently at Hysitron Inc. Minneapolis, MN, USA T: +61 2 612 50868 F: +61 2 612 50511 M: 612 600 1286 W: http://physics.anu.edu.au/eme/ **********************************
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