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Whole‐powder‐pattern fitting without reference to a structural model: application to X‐ray powder diffraction data
Author(s) -
Toraya H.
Publication year - 1986
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/s0021889886088982
Subject(s) - powder diffraction , monoclinic crystal system , diffraction , tetragonal crystal system , materials science , intensity (physics) , neutron diffraction , asymmetry , x ray crystallography , function (biology) , crystallography , x ray , analytical chemistry (journal) , optics , chemistry , physics , crystal structure , chromatography , quantum mechanics , evolutionary biology , biology
The procedure of whole‐powder‐pattern fitting without reference to a structural model, first proposed by Pawley for use with neutron powder data [ J. Appl. Cryst. (1981). 14 , 357–361], was extended as a tool for analyzing X‐ray whole‐powder data. X‐ray data for α ‐SiO 2 , α ‐Al 2 O 3 and CaCO 3 used as test samples were first analyzed by individual profile‐fitting techniques to establish the angle‐dependent profile‐shape model. Then the results were incorporated into the profile model of whole‐powder‐pattern fitting, where peak maximum positions of individual reflections are a function of unit‐cell parameters while integrated intensities are independent variables. Whole‐powder‐pattern fits for the test samples showed that the correction for peak shift has a large influence on the overall fit of the pattern and the accuracy of refined parameters. It is also important to take into account the asymmetry and the angular dependence of the intensity decay rate in modelling the diffraction profile. The method developed was applied to an analysis of the powder pattern of a mixed monoclinic tetragonal ZrO 2 .