Nonequilibrium transport through magnetic vibrating molecules

We calculate the nonequilibrium conductance through a molecule or a quantum dot in which the occupation of the relevant electronic level is coupled with intensity [lambda] to a phonon mode and also to two conducting leads. The system is described by the Anderson-Holstein Hamiltonian. We solve the problem using the Keldysh formalism and the noncrossing approximation for both the electron-electron and the electron-phonon interactions. We obtain a moderate decrease of the Kondo temperature T sub(K) with [lambda] for fixed renormalized energy of the localized level E sub(d). The meaning and value of E sub(d) are discussed. The spectral density of localized electrons shows, in addition to the Kondo peak of width 2T sub(K), satellites of this peak shifted by multiples of the phonon frequency omega sub(0). The nonequilibrium conductance as a function of bias voltage V sub(b) at small temperatures also displays peaks at multiples of omega sub(0) in addition to the central dominant Kondo peak near V sub(b) = 0.