Quantum statistical mechanical model for polarizable fluids

Abstract

The quantum statistical mechanics of a polarizable fluid model is considered using a path‐integral approach. The quantum mechanical partition function associated with the internal degrees of freedom of each molecule is approximated by a classical partition function of a polymer ring, while the center‐of‐mass motion of each molecule is treated classically. The resulting system of particles can be described by an Ornstein–Zernike equation, which we solve analytically in the mean spherical approximation. We give the dielectric constant, free energy, and internal energy of our model in both its continuum‐fluid and lattice‐gas versions. (In the former we assume hard‐sphere cores; in both versions we take harmonically oscillating dipole moments as characterizing the internal degrees of freedom, with ideal dipole–dipole intermolecular coupling.)