SPHERICAL REFERENCE SYSTEMS FOR HARD DUMBELLS

Spherical reference systems for use in perturbation theories of hard dumbell molecules are investigated. In particular the reference potential obtained by angle averaging the Boltzmann factor of the full molecular potential (€eff) is shown to lead to reasonable pair distribution functions, but to pressures much lower than those of the full hard dumbell system, whereas an effective hard sphere reference potential can be designed to give pressures in close agreement to those of the full system, though it fails to give reasonable pair distribution functions. The eeff reference system properties are calculated using a new iterative solution of the Percus-Yevick equation for soft cores. These results are compared with a Monte Carlo simulation of the same system. © 1979 Taylor & Francis Ltd.