The structure of the homonuclear diatomic solids revisited

Abstract

The relative stability of various crystal packings of a homonuclear diatomic molecule is investigated as a function of the anisotropy in the intermolecular atom-atom potential. It is shown that different crystal structures can be predicted if the electrostatic interaction arises from a quadrupolar rather than dipolar distortion of the atoms from spherical, for the same total quadrupole moment, and that the corresponding anisotropy in the repulsion-dispersion potential also plays a significant role in determining the minimum energy crystal structure. These results are used to account for the diverse experimental crystal structures of the homonuclear diatomics in terms of their valence electron distribution, and provide a starting point for the development of realistic intermolecular model potentials.