Theory of amplification and generation of light in activated solutions in the presence of intermolecular relaxation

An analysis is made of the intermolecular relaxation processes in activated solutions, which transform a two-level system of vibronic states of the activator molecules to a four-level system. It is shown that this alters considerably the main relationships in the theory of amplification and generation of light in activated solutions. More rigorous relationships obtained in the new model predict changes (in the course of pumping) not only of the intensity but generally also of the position and form of the absorption and luminescence spectra of such solutions, which should help in the interpretation of the known and new stimulated emission phenomena.