AVS 54th International Symposium | |
Surface Science | Monday Sessions |
Session SS2-MoA |
Session: | Electronic and Vibrational Structure |
Presenter: | H. Ueba, The University of Toyama, Japan |
Correspondent: | Click to Email |
I will discuss an idea of action spectroscopy for a single molecule motion induced by vibrational excitation with a scanning tunneling microscope (STM).1 A simple formula describing the energy transfer from the vibrational mode excited by tunneling electrons to a reaction coordinate mode through anharmonic coupling to overcome the activation barrier2,3 is combined with the inelastic tunneling current calculated using the non-equilibrium Keldysh Green's function method. This enables the reaction rate to be calculated as a function of the bias voltage, and is applied to CO hopping on Pd (110)2 and CCH rotation on Cu(001).4 I propose that the second-derivative of the reaction rate with respect to the bias voltage gives the density of states of the vibrational mode excited by tunneling electrons,4 which can not be directly observed with inelastic tunneling spectroscopy because of the negative contribution of the elastic current to the total current, and when a molecule motion is induced by the vibrational excitation.
1H. Ueba, B.N.J. Persson, Phys. Rev. B 75, 041403(R) (2007).
2T. Komeda et al., Science 255, 2055 (2002).
3B.N.J. Persson, H. Ueba, Surf. Sci. 502/503, 18 (2002).
4L.J. Lauhon, W. Ho, Surf. Sci. 451, 219 (2000).