Intermolecular vibrations of solid carbon dioxide

The low-frequency lattice vibrations of solid carbon dioxide are calculated using an intermolecular force law between pairs of molecules based on a Lennard-Jones 6–12 potential and electric quadrupole interactions. For zero wave-vector, it is possible to separate motions into pseudo-translational and pseudo-rotational types. Results are compared with available data from infra-red and Raman spectroscopy, and the nature of the normal modes is described.