Clebsch−Gordan coefficients for crystal space groups

Abstract

A practical method for calculating Clebsch−Gordan coefficients for crystal space groups is presented. It is based on properties of the space group irreducible representations as induced from ray representations of subgroups. Using this method, we obtain all Clebsch−Gordan coefficients for a family of representations in a single calculation: For space groups, for a given triangle of stars *k, *k′, *k″, where *k ⊗ *k′ - *k″, the coefficients for all allowable little group representations l, l′, l″ are obtained. In the following paper this is applied to rocksalt O5h−Fm3m and diamond O7h−Fd3m space groups.