The dynamics of solid cubane

Abstract

Molecular solids are an intriguing class of materials in which molecules rather than individual atoms make up the underlying lattice. Because molecules possess rotational degrees of freedom that single atoms do not, molecular solids can exhibit orientational phase transitions. At sufficiently high temperatures the molecules can enter into a phase where they rotate about one or more axes, instead of librating about a fixed angular orientation as they do at low temperatures. Perhaps the best known molecular solid is solid C₆₀ which is composed of nearly spherical molecules that exhibit a first-order orientational phase transition precisely because the C₆₀ molecular symmetry deviates slightly from that of a sphere.