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Robust Rietveld refinement in the presence of impurity phases
Author(s) -
David W. I. F.
Publication year - 2001
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/s0021889801011396
Subject(s) - impurity , rietveld refinement , context (archaeology) , diffraction , phase (matter) , materials science , chemistry , physics , optics , geology , paleontology , organic chemistry
A modified least‐squares analysis is presented that allows reliable structural parameters to be extracted from a powder diffraction pattern even in the presence of a substantial unmodelled impurity contribution. The algorithm is developed within the context of Bayesian probability theory. Experimental points that fall above those calculated, and are thus more probably from impurity peaks, are systematically down‐weighted. This approach is illustrated with a two‐phase example.