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A simple correction for the parallax effect in X‐ray pair distribution function measurements
Author(s) -
Marlton Frederick,
Ivashko Oleh,
Zimmerman Martin v.,
Gutowski Olof,
Dippel Ann-Christin,
Jørgensen Mads Ry Vogel
Publication year - 2019
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576719011580
Subject(s) - parallax , diffraction , simple (philosophy) , function (biology) , interpretation (philosophy) , pair distribution function , focus (optics) , distribution function , optics , distribution (mathematics) , process (computing) , physics , scattering , powder diffraction , statistical physics , algorithm , computer science , mathematics , mathematical analysis , artificial intelligence , quantum mechanics , nuclear magnetic resonance , philosophy , epistemology , evolutionary biology , biology , programming language , operating system
Total scattering and pair distribution function (PDF) analysis has created new insights that traditional powder diffraction methods have been unable to achieve in understanding the local structures of materials exhibiting disorder or complex nanostructures. Care must be taken in such analyses as subtle and discrete features in the PDF can easily be artefacts generated in the measurement process, which can result in unphysical models and interpretation. The focus of this study is an artefact called the parallax effect, which can occur in area detectors with thick detection layers during the collection of X‐ray PDF data. This effect results in high‐ Q peak offsets, which subsequently cause an r ‐dependent shift in the PDF peak positions in real space. Such effects should be accounted for if a truly accurate model is to be achieved, and a simple correction that can be conducted via a Rietveld refinement against the reference data is proposed.