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A General Theory of X-ray Intensity Statistics for Twins by Merohedry

Rees, D. C. (1982) A General Theory of X-ray Intensity Statistics for Twins by Merohedry. Acta Crystallographica. Section A, Foundations of Crystallography, 38 (2). pp. 201-207. ISSN 0108-7673. doi:10.1107/S056773948200045X.

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A general theory of X-ray intensity statistics for twins by merohedry is developed based on mathematical analogy of this problem to a one-dimensional random walk. Probability distribution functions are derived (a) for intensities from a single twinned specimen, and (b) for the differences in intensities from two separate twinned specimens. Theoretical values of a discrepancy index between observed intensities from a twin, and calculated intensities from both correct and incorrect structural models are evaluated. A new method for determining volume fractions of crystals in a twin is also proposed, based on the distribution of differences in intensities between twin-related reflections. These results have implications for the treatment of isomorphous replacement data collected from twins by hemihedry.

Item Type:Article
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Rees, D. C.0000-0003-4073-1185
Additional Information:© 1982 International Union of Crystallography. Received 24 March 1980; accepted 17 September 1981.
Issue or Number:2
Record Number:CaltechAUTHORS:20150210-100141163
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:54652
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Deposited On:11 Feb 2015 00:05
Last Modified:10 Nov 2021 20:36

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