Propagation of uncertainty in experiment: structures of Ni (II) coordination complexes

Schalken, Martin J.; Chantler, Christopher T.

doi:10.1107/s1600577518006549

Cited by 13 publications

(45 citation statements)

References 47 publications

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“…We could find the methods similar to the TS analysis in the paper, which were called as brute force approach [24−28] or grid search method [29]. These methods were adjunctive estimation or the refinement of fitted parameters after curve fitting analyses.…”

Section: A Features Of Ts Analysismentioning

confidence: 99%

Thorough Search Analysis of Extended X-ray Absorption Fine Structure Data for Complex Molecules and Nanomaterials Applications

Kido

Uemura

Wakisaka

et al. 2020

e-J. Surf. Sci. Nanotechnol.

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Extended X-ray absorption fine structure (EXAFS) plays an important role in the surface science and nanotechnology to characterize the non-crystalline materials using the curve fitting (CF) analysis. However, the CF has problems such as correlation between the structural parameters, the dependence on initial parameters, and the limitation of degree of freedom when EXAFS is applied to the complex system. In this paper, we propose a thorough search (TS) method to solve these problems. We analyzed EXAFS data for molybdenum oxide (α-MoO3) using the TS method. MO 3 possesses a well-defined but complex local structure in which a central molybdenum (Mo) atom is surrounded by six oxygen (O) atoms. In CF analysis, the correlations of these six Mo−O bonds make it very difficult to derive reliable structural parameters from EXAFS data. In the TS analysis, the structural parameters regarded as a point () were surveyed thoroughly over a certain range. The goodness of fit was evaluated by R-factor. All with R-factors less than a certain value were accepted. The accepted points made a domain in which it was assumed that all points in the domain should occur with equal probability and consequently their averages were used as representative structural parameters. If multiple independent domains were obtained, they were all regarded as possible candidates and the TS analysis provided possible structural parameters. The feasibility and advantages of the TS method were compared with the CF analysis and the micro reverse Monte Carlo method.

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Section: A Features Of Ts Analysismentioning

confidence: 99%

Thorough Search Analysis of Extended X-ray Absorption Fine Structure Data for Complex Molecules and Nanomaterials Applications

Kido

Uemura

Wakisaka

et al. 2020

e-J. Surf. Sci. Nanotechnol.

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“…The fine-structure function ðkÞ was extracted from each of the absorption edges by using the Mu2Chi non-interpolation background subtraction software (Schalken & Chantler, 2018). By first finding the edge energy E 0 (Kraft et al, 1996), fitting and then removing a spline, Mu2Chi returns the finestructure function in k space,…”

Section: Pre-analysis and Feff8 Analysismentioning

confidence: 99%

“…al., 1998) as input to the eFEFFIT computational package (Schalken & Chantler, 2018). The theoretical spectra are calculated using the photoelectron wave model (Lee & Pendry, 1975;Barton & Shirley, 1985b) and expressed as a sum of scattering paths through the XAFS equation (Zabinsky et al, 1995),…”

Section: Tablementioning

confidence: 99%

“…XAFS analyses of zinc selenide and most structural determination have investigated the Fourier transform of the fine-structure function (Diop & Grisenti, 1995;Kwon & Park, 2014) where uncertainties are often not propagated or estimated (Cooper et al, 2015). The use of modern computational modelling with full propagation of experimental errors (Schalken & Chantler, 2018) allows for a more robust analysis than previously obtainable.…”

Section: Introductionmentioning

confidence: 99%

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High accuracy determination of photoelectric cross sections, X-ray absorption fine structure and nanostructure analysis of zinc selenide using the X-ray extended range technique

Sier

Cousland

Trevorah

et al. 2020

J Synchrotron Radiat

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Measurements of mass attenuation coefficients and X-ray absorption fine structure (XAFS) of zinc selenide (ZnSe) are reported to accuracies typically better than 0.13%. The high accuracy of the results presented here is due to our successful implementation of the X-ray extended range technique, a relatively new methodology, which can be set up on most synchrotron X-ray beamlines. 561 attenuation coefficients were recorded in the energy range 6.8–15 keV with measurements concentrated at the zinc and selenium pre-edge, near-edge and fine-structure absorption edge regions. This accuracy yielded detailed nanostructural analysis of room-temperature ZnSe with full uncertainty propagation. Bond lengths, accurate to 0.003 Å to 0.009 Å, or 0.1% to 0.3%, are plausible and physical. Small variation from a crystalline structure suggests local dynamic motion beyond that of a standard crystal lattice, noting that XAFS is sensitive to dynamic correlated motion. The results obtained in this work are the most accurate to date with comparisons with theoretically determined values of the attenuation showing discrepancies from literature theory of up to 4%, motivating further investigation into the origin of such discrepancies.

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“…pe versus E for two 15 mM Ni complexes from fluorescence measurements in two formats, namely a prototype errorpropagating input suitable for eFEFFIT (Schalken & Chantler, 2018) and IFEFFIT input, and a prototype IUCr CIF data format.…”

Section: A Key Problem In General X-ray Fluorescence Analysismentioning

confidence: 99%

Solving self-absorption in fluorescence

Trevorah

Chantler

Schalken

2019

IUCrJ

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One of the most common types of experiment in X-ray absorption spectroscopy (XAS) measures the secondary inelastically scattered fluorescence photon. This widespread approach has a dominant systematic of self-absorption of the fluorescence photon. The large impact of self-absorption compromises accuracy, analysis and insight. Presented here is a detailed self-consistent method to correct for self-absorption and attenuation in fluorescence X-ray measurements. This method and the resulting software package can be applied to any fluorescence data, for XAS or any other experimental approach detecting fluorescence or inelastically scattered radiation, leading to a general solution applicable to a wide range of experimental investigations. The high intrinsic accuracy of the processed data allows these features to be well modelled and yields deeper potential insight.

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Propagation of uncertainty in experiment: structures of Ni (II) coordination complexes

Cited by 13 publications

References 47 publications

Thorough Search Analysis of Extended X-ray Absorption Fine Structure Data for Complex Molecules and Nanomaterials Applications

Thorough Search Analysis of Extended X-ray Absorption Fine Structure Data for Complex Molecules and Nanomaterials Applications

High accuracy determination of photoelectric cross sections, X-ray absorption fine structure and nanostructure analysis of zinc selenide using the X-ray extended range technique

Solving self-absorption in fluorescence

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