Interactions in Polar Media. II. Continua

Abstract

It is shown that the electronically polarizable continuum model of a particle satisfies the equations of part I, after suitable choice of operator A_i appearing there. The proof is given for the case where the system is regarded as composed of particles and treated statistically mechanically. It is also given for the case where several particles receive special attention and the remainder of the system (the "medium") is treated as an orientationally and electronically polarizable continuum. For the second case it was necessary to extend the results of Part I, so as to include several particles in the presence of the above "medium" and to compute the free energy of such systems. Calculations are given for media possessing equilibrium and nonequilibrium dielectric polarization. It follows from the foregoing proofs that a wide variety of models assumed in the literature for treating polar interactions are special cases of the model in Part I and of the extension to particle‐medium systems in this paper. Electrode systems, for example, are included, even when the electrode is treated in the usual dielectric continuum manner. The relation and relative merits of the two models for the induced charge distribution that are standard in the literature, both special cases of Part I, are discussed. These models are the induced dipole and the electronically polarizable continuum. Possible direct experimental investigation of the second of these by scattering experiments is examined.