Trial-and-error computer methods for the indexing of unknown powder patterns

Abstract

A number of programs for facilitating the indexing of powder patterns, based essentially on trial-and-error methods, have been constructed for the electronic computers BESK and Facit EDB. The methods are efficient also for the analysis of powder patterns in which lines are missing either by accident or because of translational symmetry. The programs presuppose monoclinic or higher symmetry. The principles used are illustrated with three powder patterns. It should be possible to adapt the methods to any digital computer.