Abstract
The Coulomb potential due to a periodic array of point multipoles is found and expressed, in terms of the multipole moments and dimensionless Ewald coefficients, in a form convenient for energy-band calculations by the augmented-plane-wave method. The formalism is then applied to an array of multipoles having the symmetry of the crystal lattice. Numerical values are given for the Ewald coefficients for a monatomic body-centered cubic crystal. © 1969 The American Physical Society.