Theory of Vibrational Structure in Optical Spectra of Impurities in Solids. II. Multiplets

Abstract

The results of a previous paper describing vibrational structure in the spectra of singlet‐to‐singlet optical transitions of impurities in solids are extended to a general class of multiplet‐to‐multiplet transitions. The transitions considered are those between degenerate or nondegenerate multiplets which are not interconnected by the interaction coupling the impurities to the lattice phonons. The phonon field couples impurity states within each multiplet but does not couple states in different multiplets. The results apply to systems which display strong Jahn‐Teller distortions as well as to those which do not. As a specific application of our results we consider the singlet‐to‐doublet transitions of simple three‐level systems having C₃ and C_3v symmetry.