Ifeffit

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ifeffit@millenia.cars.aps.anl.gov

October 2024

3 participants
2 discussions

Problem with fit data export
by Otal Eugenio 17 Oct '24

17 Oct '24

Dear all, I was exporting the filtered data and found Larch is not exporting the filtered data. No new files were found in the folder I was saving the files. I found a victory in doing it from the plotting window after fitting, File > Export data. I exported the chi(k) with chi(q), chi(k) with the fit and chi(q) with the fit. All included bellow. The signal in chi(k) with its fit and chi(q) with its fit, both match well. The fit shown chi(k) and chi(q) has different aspects. Am I wrong or the fit should look the same in both cases? Is there any compensation for the window used? Do I need to change something in the configuration to export it properly? Best regards [image: image.png] [image: image.png] [image: image.png] (^ㅇᆽㅇ^)(=˃ᆺ˂=)(=🝦 ༝ 🝦=) Eugenio H. OTAL Assistant Professor Research Initiative for Supra Materials, Shinshu University 4-17-1 Wakasato, Nagano city. 380-8553, Japan eugenio_otal(a)shinshu-u.ac.jp ¯\_(ツ)_/¯¯\_(ツ)_/¯ Who is John Galt? ¯\_(ツ)_/¯¯\_(ツ)_/¯

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Retrieving errors (uncertainties) for sigma2 = eins(temperature, thetae) in Artemis
by albeiro.henaow＠gmail.com 11 Oct '24

11 Oct '24

I am modeling the Debye-Waller factor by using the Einstein model in Artemis, where the Einstein temperature (thetae) is a guess parameter and sigma2 is a defined parameter as eins(temperature, thetae). Although, after running the fit, the error for the estimation of thetae is given by the fit report, the error for the corresponding defined sigma2 is missing. I am working on some models to reduce the errors in the estimation of the Debye-Waller factor, so it's an important value for my research. I tried to propagate the errors by using the equation in the ref paper (E. Sevillano, H. Meuth, and J. J. Rehr. Extended x-ray absorption fine structure Debye-Waller factors. I. Monatomic crystals. Phys. Rev. B, 20:4908–4911, Dec 1979. doi:10.1103/PhysRevB.20.4908.) However, I cannot obtain the same value of sigma2 when I substitute thetae into the equation from the paper compared to the value reported in the fit. Can anyone help clarify the equation (or script) used in Artemis? Thank you! Wilson Henao

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