On the role of solvent in formation and relaxation of molecular exciplex

The processes of formation and of relaxation of molecular exciplex in solution are discussed in the framework of method which incorporates solvent parameters into calculations of potential energy curves of different states attainable by exciplex system. An analysis of the results of calculations shows that intramolecular vibrations are serving as acceptors for energy dissipated by the system in the formation process and that this accepting ability can be modified by solvent polarity. It is also shown that the most important role is played by solvent in the relaxation of encounter complex to “equilibrium” exciplex.