Electron-phonon interaction of strongly correlated systems. II. Strong coupling limit

The Hubbard–Holstein model containing interaction between localized electrons and dispersionless phonons is investigated. The frequency of collective mode of the phonon cloud surrounding the polaron is determined in the strong coupling limit. The influence of this mode on the radiation and adsorption processes in the energy spectrum of both localized and delocalized polarons is established. The motion of delocalized polarons is described in the chain diagram approximation, without taking into account multiparticle irreducible Green functions of polarons.