Intermolecular Bonding in the Solid Halogens

The band structure of solid iodine is worked out on the assumption that electron exchange between layers is negligible and that only p functions are used by the iodine atoms. The model is justified by its simple description of the iodine nuclear quadrupole coupling constant, the anisotropy of the electrical conductivity and the optical absorption. Experiments are proposed which would provide a more detailed check of the model; the p bands of gallium and indium can probably be described by a similar tight binding scheme.