We theoretically examine the effect of the coupling of the transport electrons to a vibrational mode of the molecule on the ac linear-response conductance of molecular junctions. Representing the molecule by a single electronic state, we find that at very low temperatures the frequency-dependent conductance is mainly enhanced (suppressed) by the electron-vibration interaction when the chemical potential is below (above) the energy of that state. The vertex corrections of the electron-vibration interaction induce an additional peak structure in the conductance, which can be observed by tuning the tunnel couplings with the leads.
@article{arxiv.1101.4440,
title = {Effects of coupling to vibrational modes on the ac conductance of molecular junctions},
author = {A. Ueda and O. Entin-Wohlman and A. Aharony},
journal= {arXiv preprint arXiv:1101.4440},
year = {2015}
}