DYNAMICS AND OPTICAL-SPECTRA OF AN EXCITON IN A DEFORMABLE LATTICE

The dynamics of an exciton strongly interacting with phonons are studied by calculating the optical absorption and the secondary-emission spectra in a new effective-medium approximation which is an extension of the dynamical coherent potential approximation. Relations between spectral line shapes and dynamical relaxation processes are discussed in the case of a self-trapped state being separated from a metastable free state by a potential barrier. It is shown that quantum-mechanical configurational mixing between the free state and the self-trapped state causes sizable effects on the line shape of the absorption spectrum as well as on the excitation-energy dependence of the secondary-emission spectrum. © 1990.