Theory of solvent effects on electronic spectra

We describe theory and review theoretical investigations of solvent effects on electronic spectra. We review briefly five main models for such investigations, namely the thermochemical, supermolecular, dielectric, reaction field and the statistical models. The last two models are particularly emphasized and are reviewed in more detail. The reaction field theory is described with respect to solvent response and solvent energy. The cavity model is outlined as well as the self-consistent reaction field method (SCRF) and its multi-configurational formulation (MCSCRF). Examples of the application of these models are given by studies of solvent effects on photoelectron and Auger spectra of ionic and molecular solutions. We also review solvent theory and calculations for excitation spectra and solvatochromatic shifts, illustrated with the radiative deactivation of singlet molecular oxygen as a specific example.