  The role of local electron-vibration and electron-electron interactions on
the thermoelectric properties of molecular junctions is theoretically analyzed
focusing on devices based on fullerene molecules. A self-consistent adiabatic
approach is used in order to obtain a non-perturbative treatment of the
electron coupling to low frequency vibrational modes, such as those of the
molecule center of mass between metallic leads. The approach incorporates also
the effects of strong electron-electron interactions between molecular degrees
of freedom within the Coulomb blockade regime. The analysis is based on a
one-level model which takes into account the relevant transport level of
fullerene and its alignment to the chemical potential of the leads. We
demonstrate that only the combined effect of local electron-vibration and
electron-electron interactions is able to predict the correct behavior of both
the charge conductance and the Seebeck coefficient in very good agreement with
available experimental data.
