On the theory of resonant secondary radiation of excitons weakly interacting with phonons

Formulae are obtained for the partial spectra of the resonant secondary radiation of excitons weakly interacting with optical phonons, separated from the Rayleigh line by two or three phonon frequencies. The cases of the Frenkel exciton as well as that of the Wannier‐Mott one are considered. The obtained shapes of the spectra depend upon the type of the dispersion law of the exciton band and on the type of the dependence of the exciton—phonon interaction constants on the wave vector. A classification of these spectra according to the transformation mechanism from the primary photon into secondary is made. The criteria are obtained identifying the spectra under consideration as scattering, ordinary or hot luminescence.