Effective vibrational potentials of bromine in argon. Monte Carlo simulation in a mixed ensemble

Abstract

We are concerned here with medium effects on the vibrational—rotational properties of a molecule. An efficient Monte Carlo simulation procedure is presented by, which these properties can be studied for a fixed energy of the guest molecule. This is done by extending a recently developed microcanonical sampling method to a mixed ensemble method where the a priori information is partly of a microcanonical and the remainder of a canonical character. The new method is applied to a bromine molecule at high energy in an argon medium at several temperatures and densities. The dependence of the bond length on the medium is illustrated and an effective vibrational potential including medium effects is obtained by a microcanonical inversion procedure.