February 2025 - Ifeffit - millenia.cars.aps.anl.gov

Constraining phase composition
by Olena Zavorotynska 09 Feb '25

09 Feb '25

Hello, I have been fitting in Artemis three phases to my samples, that I denote x, y, and 1-(x+y). It often happens that x and y get unreasonable or negative values. How do I constrain x, y to be positive, and x+y < 1? On a side note, I have simple metallic lattices, and fitting two samples at the same time so have enough independent points. Best regards Olena Zavorotynska Sent from my Galaxy

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Correcting for over absorption
by cameron.mollazadeh＠colorado.edu 06 Feb '25

06 Feb '25

Hi Matthew, I was re-reading the larch documentation as my data is suffering for over absorption and was wondering how I can go about implementing the correction factor. I am primarily using the data for EXAFS analysis and was also wondering if this technique is still questionable for EXAFS. Thank you! Cameron

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Re: [EXT] Ifeffit Digest, Vol 276, Issue 2
by Christopher Chantler 05 Feb '25

05 Feb '25

Hi Cameron See Trevorah R et al. regarding correction for absorption and self-absorption; Yes it is probably still suitable for EXAFS analysis subject to other criteria and constraints. Also see Schalken M et al. for the comparison of transmission EXAFS (largely without self-absorption) versus angle-dependent fluorescence EXAFS (which almost always has self-absorption and absorption in an angle-dependent manner) and how to extract the data. Note that fluorescence data has a functional which is not directly that of a transmission or absorption measurement. Best wishes Chris -------------------------------------------------------------------------------------- Christopher Chantler, Professor, FAIP, Fellow American Physical Society Editor-in-Chief, Radiation Physics and Chemistry Member, CIT, CCN; Former Chair, International Union of Crystallography Commission on XAFS International Radiation Physics Society, Former President School of Physics, University of Melbourne, Parkville Victoria 3010 Australia +61-3-83445437 FAX +61-3-93474783 chantler(a)unimelb.edu.au<mailto:chantler@unimelb.edu.au> chantler(a)me.com<https://urldefense.us/v3/__https://owa.unimelb.edu.au/owa/redir.aspx?C=c7Bo… > https://urldefense.us/v3/__https://www.ph.unimelb.edu.au/*chantler/opticsho… <https://urldefense.us/v3/__http://www.ph.unimelb.edu.au/*chantler/home.html… > https://urldefense.us/v3/__https://www.ph.unimelb.edu.au/*chantler/opticsho… ________________________________ From: ifeffit-request(a)millenia.cars.aps.anl.gov <ifeffit-request(a)millenia.cars.aps.anl.gov> Sent: Wednesday, 5 February 2025 5:00 PM To: ifeffit(a)millenia.cars.aps.anl.gov <ifeffit(a)millenia.cars.aps.anl.gov> Subject: [EXT] Ifeffit Digest, Vol 276, Issue 2 External email: Please exercise caution Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe 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. Correcting for over absorption (cameron.mollazadeh(a)colorado.edu) 2. In reference to the prior overabsorption (Cameron Mollazadeh) ---------------------------------------------------------------------- Message: 1 Date: Mon, 03 Feb 2025 21:59:27 -0000 From: cameron.mollazadeh(a)colorado.edu Subject: [Ifeffit] Correcting for over absorption To: ifeffit(a)millenia.cars.aps.anl.gov Message-ID: <173861996743.2557830.8195040248000522658(a)millenia.cars.aps.anl.gov> Content-Type: text/plain; charset="utf-8" Hi Matthew, I was re-reading the larch documentation as my data is suffering for over absorption and was wondering how I can go about implementing the correction factor. I am primarily using the data for EXAFS analysis and was also wondering if this technique is still questionable for EXAFS. Thank you! Cameron ------------------------------ Message: 2 Date: Mon, 3 Feb 2025 22:01:09 +0000 From: Cameron Mollazadeh <Cameron.Mollazadeh(a)colorado.edu> Subject: [Ifeffit] In reference to the prior overabsorption To: Cameron Mollazadeh via Ifeffit <ifeffit(a)millenia.cars.aps.anl.gov> Message-ID: <SN6PR03MB4592175B3E3C1276F36D33F9F1F52(a)SN6PR03MB4592.nam prd03.prod.outlook.com> Content-Type: multipart/related; boundary="_004_SN6PR03MB459217 5B3E3C1276F36D33F9F1F52SN6PR03MB4592namp_"; type="multipart/alternative" Here is a photo of the “normalized” spectra [cid:image001.png@01DB764C.751787B0] Best, Cameron Mollazadeh PhD Student | Toney Group | CU Boulder

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In reference to the prior overabsorption
by Cameron Mollazadeh 03 Feb '25

03 Feb '25

Here is a photo of the “normalized” spectra [cid:image001.png@01DB764C.751787B0] Best, Cameron Mollazadeh PhD Student | Toney Group | CU Boulder

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Athena .dat file
by Raspante, Fabio 01 Feb '25

01 Feb '25

Hi, I worked on some data and I aligned them properly before to do any comparison. I also checked the alignment by plotting all the data together. After that I exported the data to have a file usable on Origin (the .dat format) but the problem is that after plotting the data on Origin, they are not aligned anymore. Specifically one group of data is not aligned to the others. Do you know what could be the problem? And how can I solve it? Many thanks, Fabio

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