抄録
The convex-core model of molecules, which has been effective for discussing thermodynamic properties of polyatomic gases, is applied to the crystals of benzene and ethylene as a continuation of a previous article of the same title, in which crystals of methane, carbon dioxide, and nitrogen were treated. By use of model parameters determined from the second virial coefficients, cohesive energies and lattice constants are calculated. When we neglect zero-point energies, potential non-additivities, and electric multipole interactions, then the calculated cohesive energies are close to the observed values for benzene and 16% higher for ethylene. The calculated lattice constants agree well with observed ones in both cases. Stability of the benzene crystal is discussed, but the conclusions are not as definite as in the case of carbon dioxide.
