Vibronic effects in single molecule conductance: First-principles description and application to benzenealkanethiolates between gold electrodes

The effect of vibrational motion on resonant charge transport through single molecule junctions is investigated. The study is based on a combination of first-principles electronic structure calculations to characterize the system and inelastic scattering theory to calculate transport properties. The extension of the methodology to describe hole transport through occupied molecular orbitals is discussed. The methodology is applied to molecular junctions where a benzene molecule is connected via alkanethiolate bridges to two gold electrodes. The results demonstrate that, depending on the coupling between the electronic π-system of the benzene ring and the gold electrodes, vibronic coupling may have a significant influence on the transport properties of the molecular junction.