The reliability of unit cells derived from powder diffraction patterns

Abstract

It is shown that the reliability of a unit cell, obtained by indexing a powder pattern, depends on the ratio of the actual discrepancies to the average discrepancies A which would result from an arbitrary unit cell of the same Bravais type and of about the same size. Expressions for A, for all non-cubic Bravais types of lattice, are derived from statistical considerations based on the number of calculated lines below a given Bragg angle.