Vibrational partition functions for atom–diatom and atom–triatom van der Waals systems

Abstract

The vibrational partition functions of atom–diatom and atom–(linear triatom) van der Waals complexes are calculated directly within the classical statistical mechanics formalism by using a Monte Carlo procedure. Constrained classical Hamiltonians for these molecular systems have been derived by constraining the internal coordinates of the chemically bound molecules to their equilibrium values. The method is applied to the Ar⋯CN and Ar⋯HCN van der Waals molecules, and the results compared with previously reported ones.