A STUDY OF THE PERFECTLY ORIENTED GAY-BERNE MODEL OF A NEMATIC LIQUID-CRYSTAL VIA PERTURBATION-THEORY AND MOLECULAR-DYNAMICS

A perturbation theory for the Gay-Berne interaction potential has been developed and selected results are compared with those of molecular d ynamics simulations for the same model. The perturbation method can be regarded as a generalization to oriented molecular fluids of the Week s-Chandler-Andersen perturbation scheme. The properties of the soft re pulsive reference system are related to a system of hard ellipsoids of revolution by the introduction of temperature and density dependent e llipsoidal axes. For the sake of simplicity and clarity both methods a re applied to the perfectly ordered nematic phase, in which all partic les are oriented in the same direction. Compressibility factors and st ructure factors were calculated via both routes for different temperat ures and show remarkable agreement. Benefits and drawbacks of the two methods are discussed.