Influence of exciton scattering correlations on the optical spectra of disordered crystals

Abstract

It is shown that the average t-matrix, single-site approximation fails when the crystal disorder is no longer represented by the Anderson model. The repeated scattering of excitons by clusters of impurity molecules should be taken into account in this case. A model calculation of the optical absorption line shapes has been performed. The asymmetric optical line broadening for impurity crystals at low temperatures is accounted for in terms of our theory.