An estimate of the number of structural parameters measurable from a fiber diffraction pattern

Abstract

An estimate of the number of independent structural parameters that can be determined from a fiber diffraction pattern is derived and its application is demonstrated. At resolutions where independent estimates can be made for the intensity of every layer line, this number is set by sampling limits along each layer line [Makowski (1982). J. Appl. Cryst. 15, 546–557]. At resolutions beyond which separation of intensities due to individual layer lines is possible (the deconvolution limit) there may still be usable structural information in the pattern. Even though intensities on individual layer lines cannot be uniquely determined from these data, the data may still represent useful constraints on structural models of the diffracting particles. Here it is shown that beyond the deconvolution limit the total number of structural parameters obtainable increases linearly as a function of resolution.