PERTURBATION-RESPONSE THEORY AS A BASIS FOR THE CONTINUUM MODELS OF SOLVATION - INCLUSION OF THE POLARIZATION

A perturbation-response approach to the description of the solvation p rocess, based on time-independent perturbation theory of solute/solven t interactions, is considered. The analysis is developed under the ass umption of strong-orthogonality between solute and solvent states, whi ch corresponds to the hypothesis of a fixed cavity. The analytical res ults are interpreted within linear response theory for condensed syste ms and are expressed in terms of (assumed unperturbed) macroscopic die lectric functions of the solvent, thus allowing a link to the correspo nding formulae of continuum models for solvation. The zeroth-and first -order response of both the solute and the solvent sub-systems are ana lyzed in detail in two model cases, in which the solute is described b y one and two electronic states respectively. Particular attention is devoted to distinguishing-at room temperature-the contributions due to acoustic/orientational solvent excited states from those due to vibra tional/electronic ones. Relationships with previous efforts along simi lar lines are also discussed. (C) 1998 Elsevier Science B.V.