The efficiency of resonant light scattering on excitons.

We discuss the validity of various theories of resonant light scattering by phonons. We specially consider the case of an exciton-phonon coupling which is small compared to the exciton-photon coupling. Thus, for a particular choice of additional boundary conditions (ABC) the scattered intensity can be calculated self-consistently with, parameters deduced from the experiments. We discuss several experiments, of the literature and the problem of ABC. Elastic scatterings by defects are also considered. [ABSTRACT FROM AUTHOR]