Ab initio study of the alternating current impedance of a molecular junction

The small-bias conductance of the C ₆ molecule, stretched between two metallic leads, was analyzed. The time-dependent density functional theory within the adiabatic local density approximation was used for the analysis. The alternating current fluctuations of charge and currents within the molecule and the metallic leads were observed. It was found that the fluctuations form the complex impedance of the molecule and are especially strong at the plasmon frequency of the leads.