Dissociation Reaction of an Isolated (CH₃S)₂ Molecule and Hopping Motion of an Isolated CH₃S Molecule Adsorbed on Cu(111)

Abstract

The S-S bond dissociation in an isolated (CH₃S)₂ molecule and the hopping motion of an isolated CH₃S molecule on Cu(111) surface were induced by the injection of tunneling electrons from the tip of a scanning tunneling microscope (STM). From the bias voltage dependence for the S-S bond dissociation probability, it was shown that the vibrational excitations of a C-H stretching mode and a combination mode of C-H stretching and S-S stretching in the molecule are responsible for the dissociation reaction induced by inelastically tunneled electrons, respectively. From the bias voltage dependence for the hopping probability of an isolated CH₃S molecule on Cu(111) surface, it was shown that the vibrational excitation of C-S stretching in the molecule is strongly contributed to this motion. In the present study, the projected density of state and molecular orbital were also calculated for each adsorption system. From these results, we propose that the molecular vibration induced by the injection of tunnel electrons can be explained by the resonant mechanism.