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Unit‐cell refinement from powder diffraction scans
Author(s) -
Pawley G. S.
Publication year - 1981
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/s0021889881009618
Subject(s) - usable , powder diffraction , neutron diffraction , diffraction , resolution (logic) , point (geometry) , unit (ring theory) , computer science , materials science , crystallography , quality (philosophy) , crystal (programming language) , algorithm , physics , optics , chemistry , mathematics , geometry , artificial intelligence , programming language , mathematics education , quantum mechanics , world wide web
A procedure for the refinement of the crystal unit cell from a powder diffraction scan is presented. In this procedure knowledge of the crystal structure is not required, and at the end of the refinement a list of indexed intensities is produced. This list may well be usable as the starting point for the application of direct methods. The problems of least‐squares ill‐conditioning due to overlapping reflections are overcome by constraints. An example, using decafluorocyclohexene, C 6 F 10 , shows the quality of fit obtained in a case which may even be a false minimum. The method should become more relevant as powder scans of improved resolution become available, through the use of pulsed neutron sources.