Structure and dynamics of associated molecular systems. II. Atom–atom potentials and the properties of ammonia

The properties of ammonia are briefly reviewed. Recently proposed models for the intermolecular forces between ammonia molecules are tested by calculating selected properties other than those used in their parameterization. Results are reported for the second virial coefficient of the gas, the zero wave vector lattice frequencies of the solid, and the atomic pair distribution functions for the liquid. It is concluded that none of the existing atom–atom models is entirely satisfactory.