Dear everyone, I am looking for XAS data of Ni2+ ion in aqueous solution that contains EXAFS data in the k range of 0-12 (Angstrom-1) or so for an undergraduate student project. I was wondering if anyone would be willing to share the data with me? Many thanks in advance. Best, Van On Fri, Apr 21, 2017 at 5:02 AM, Christopher Thomas Chantler < chantler@unimelb.edu.au> wrote:

Note that in general any and every smoothing operation reduces the information content of the data and its ability to reveal structure. Also, many of the smoothing algorithms change the data point values at vertices, so change the data prior to analysis.

Hence in general avoid unless you know exactly the physical cause requiring smoothing.

Best wishes

------------------------------------------------------------ -------------------------- Christopher Chantler, Professor, FAIP, Fellow American Physical Society Editor-in-Chief, Radiation Physics and Chemistry Chair, International IUCr Commission on XAFS President, International Radiation Physics Society School of Physics, University of Melbourne Parkville Victoria 3010 Australia +61-3-83445437 FAX +61-3-93474783 chantler@unimelb.edu.au https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdAITgSrfUpfDAUV5oUH1LFYBcz08w8xvHMJoosZRdagfQM.&URL=mailto%3achantler%40unimelb.edu.au chantler@me.com https://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.html https://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.html https://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:* Friday, 21 April 2017 3:00:01 AM *To:* ifeffit@millenia.cars.aps.anl.gov *Subject:* Ifeffit Digest, Vol 170, Issue 19

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Today's Topics:

1. Re: The difference of EXAFS oscillation when using Athena and when using Larch (Yuji Mahara)

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Message: 1 Date: Thu, 20 Apr 2017 19:47:20 +0900 From: "Yuji Mahara" To: "'XAFS Analysis using Ifeffit'" Subject: Re: [Ifeffit] The difference of EXAFS oscillation when using Athena and when using Larch Message-ID: <003501d2b9c3$7c75c560$75615020$@e.mbox.nagoya-u.ac.jp> Content-Type: text/plain; charset="utf-8"

Dear Matt

Thank you for your reply.

I confirmed that chi (k) becomes smooth by the Savitzky-Goley method by doing the attached lar file.

I will try on various conditions from now.

I may also ask if there is something I do not understand.

Thank you for your help again!

Bests,

Yuji Mahara

From: Ifeffit [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov ] On Behalf Of Matt Newville Sent: Thursday, April 20, 2017 5:26 AM To: XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] The difference of EXAFS oscillation when using Athena and when using Larch

Hi Yuji,

The attached larch script (a modification of your script but note: not python, so you may have to add a bunch of '_larch=mylarch' arguments) to show the effects of smoothing with Savitzky-Golay and of interpolating onto a "classic XAFS energy grid". You might want to play around with this different options. It definitely seems that none of these methods are systematically over-smoothing the data and reducing the amplitudes of the oscillations -- one more reason to use Larch instead of Ifeffit. But it also seems like smoothing this data with a Savitzky-Golay fitler is helpful.

Also attached are plots showing k- and R-space generated from the attached script.

--Matt