The Orientation Effect on Inelastic Electron Tunneling Spectroscopy in Octanethiolate Molecular Junctions

Abstract

A first-principles computational method is developed to study the inelastic electron tunneling spectroscopy (IETS) of octanethiolate molecular junctions with different orientation of the molecule adsorbed on the Au(111) surface. We have demonstrated that IETS is very sensitive to the orientation of the molecule. The computational results demonstrate that the IETS has certain selection rule for vibrational modes, where the modes with the same direction as the tunneling current have greatest contribution to the IETS.