Resistance of Alkanethiol Molecular Wires

We use a first-principles technique to calculate the length dependence of resistance of alkanethiol wires in the metal−alkanethiol−metal configuration. The current−voltage characteristics of the wires are found to be largely linear, and the small bias resistance increases exponentially with the molecule length. We also investigate the effects of changes at the metal−molecule junction, including the contact geometry, end-groups, and junction distance. We compare theoretical results with recently reported experimental data.