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On the numerical corrections of time‐of‐flight neutron powder diffraction data
Author(s) -
Avdeev Maxim,
Jorgensen James,
Short Simine,
Von Dreele Robert B.
Publication year - 2007
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/s0021889807030014
Subject(s) - rietveld refinement , voigt profile , convolution (computer science) , neutron diffraction , exponential function , exponent , neutron , diffraction , time of flight , computational physics , gaussian , physics , powder diffraction , nist , gaussian function , function (biology) , statistical physics , materials science , mathematics , mathematical analysis , optics , nuclear physics , nuclear magnetic resonance , computer science , quantum mechanics , spectral line , linguistics , philosophy , machine learning , evolutionary biology , natural language processing , biology , artificial neural network
Time‐of‐flight neutron powder diffraction data for NIST Standard Reference Materials have been used to study the adequacy of the peak profile model obtained from a convolution of back‐to‐back exponentials with a pseudo‐Voigt function that is widely used in Rietveld refinement. It is shown that, while the empirical models for d ‐spacing (wavelength) dependence of Gaussian and Lorentzian components of the pseudo‐Voigt function and rise exponent are satisfactory, the behavior of the decay exponent and peak positions demonstrate significant deviations, which can be corrected by numerical methods. The practical side of this process as implemented in GSAS and FULLPROF and the effect of the corrections on the Rietveld analysis results are discussed.