A theoretical analysis of inelastic electron tunneling spectroscopy (IETS)
experiments conducted on molecular junctions are presented, where the second
derivative of the current with respect to voltage is usually plotted as a
function of applied bias. Within the nonperturbative computational scheme,
adequate for arbitrary parameters of the model, we consider the virtual
conduction process in the off-resonance region. Here we study the influence of
few crucial factors on the IETS spectra: the strength of the vibronic coupling,
the phonon energy, and the device working temperature. It was also shown that
weak asymmetry in the IETS signal with respect to bias polarity is obtained as
a result of strongly asymmetric connection with the electrodes.Comment: 9 pages, 9 figure