LOW-TEMPERATURE EQUATION OF STATE OF SOLID METHANE

The theoretical equation of state for solid methane, developed within the framework of perturbation theory, with the crystal consisting of spherical molecules as zero-order approximation, and octupole-octupole interaction of methane molecules as a perturbation, is proposed. Thermodynamic functions are computed on the sublimation line up to the triple point. The contribution of the octupole-octupole interaction to the thermodynamic properties of solid methane is estimated.