Exact Energy of Interaction Between Nonpolar Molecules Represented as Dipoles

Abstract

A new non-perturbative method is developed for deriving the energy of interaction between molecules represented as polarizable dipoles. The method is applied to obtain the exact energy of interaction for two anisotropic electric dipoles and for three dipoles in the isotropic case. The results of London and of Casimir and Polder are special limiting cases. Deviations of the London energy from the exact result are investigated. A new feature which emerges is that the potential energy becomes repulsive at very small distances of separation.