The second volume of this treatise lS concerned with three important problems: a) environmental effects b) reaction mechanisms c) photochemical processes An important paper is devoted to the solvation problem. The local field representation of surrounding medium effect is analyzed and an application is made to the study of ambident reaction. A paper is devoted to the study of chemical reactivity in inert matrices and a theory of the effect of rare gas matrices on molecules is presented. Six papers are concerned with chemical reactions mechanisms. They are related to migration reactions, nucleophilic additions and electrophilic additions, and homogeneous catalytic reactions. Finally, some aspects of the photochemical processes are discussed. The evolution of electronically excited molecules is analyzed and the natural correlation method is presented. The role of Rydberg states' is photochemistry is suggested, we believe, for the first time. The sudden polarization in olefins is described in a critical way and a new phenomenon is presented: the pho- tochemical attachment of aliphatic hydrocarbons to polynuclear aromatic hydrocarbons. vii R. Daudel, A. Pullman, L. Salem, and A.Veillard (eds.;, Quantum Theory of Chemical Reactions, Volume II, vii. Copyright (c) 1980 by D. Reidel Publishing Company. THE SUPERMOLECULE APPROACH TO THE SOLVATION PROBLEM A. PULLMAN Institut de BioLogie Physico-Chimique Laboratoire de Biochimie Theorique, associe au C.N.R.S.
