Electric field response of a vibrationally excited molecule in an STM junction

We found that a single molecule in a vibrationally excited state on a surface can be delivered precisely to a desired position with the aid of a local electric field in a scanning tunneling microscope (STM) junction. An individual CH₃S molecule on a Cu(111) surface hops laterally to move away from a negatively charged STM tip and to come toward a positively charged tip when the lateral hopping motion is induced by inelastically tunneled electrons and the molecule is positioned in an inhomogeneous electric field. These experimental findings reveal that a vibrationally excited molecule on a surface responds with high sensitivity to a local electric field in an STM junction.