Monte Carlo evaluation of path integrals: Quantal intramolecular degrees of freedom in solution

Standard many-body classical Monte Carlo methods are extended so as to allow the examination of quantal internal degrees of freedom of molecules in solution by using discretized path integral representations of the solute. It is shown how, in a variety of cases, the classical structure of the path integral helps in choosing an appropriate reference system and how recently developed methods for evaluating path integrals make practical calculations possible. The concepts are illustrated on a model of a two-state system in solution.