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The use of continuous diffraction data as a phase constraint. II. Application to fiber diffraction data
Author(s) -
Makowski L.
Publication year - 1982
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/s0021889882012564
Subject(s) - diffraction , fiber diffraction , fiber , materials science , optics , sampling (signal processing) , x ray crystallography , physics , composite material , detector
The properties of intensity data in fiber diffraction patterns are considered with the aim of developing strategies for structural studies of helical macro‐molecular assemblies. A quantitative calculation is made of the number of independent intensity measurements in a fiber diffraction pattern and the number of degrees of freedom in an image of a helical object. These calculations are based on sampling theory in cylindrical coordinates. Several novel schemes for sampling intensities in a fiber diffraction pattern are demonstrated. A class of Patterson‐like functions are introduced that may be useful in determining the helical symmetry of a particle from diffraction data. The use of these results in determining the significance of details of structural models based on fiber diffraction data is discussed.