Bias voltage dependence on the vibronic electric current

We discuss bias voltage effects on the elastic and the inelastic currents in the tunneling region. We have derived and solved two self-consistent loops: one for electron-electron interaction within the Hartree-Fock approximation, and another for the electron-intramolecular vibration coupling within the Born approximation. The formalism is based on Keldysh Green's function theory; numerical calculations were made in terms of ab initio quantum chemistry techniques augmented with a model for the electrodes. While no remarkable voltage effect on the vibronic currents was found in the low-bias voltage region, we found significant bias voltage effect in the high-bias voltage region. The suppressive correlation between the elastic and the inelastic components of the current is reduced because of the molecular orbital energy shift in the latter region.