ABSTRACT
The characterization of single molecular junctions is essential to understanding their properties, including their electronic, magnetic, and optical properties. Vibration spectroscopy is a powerful technique for characterizing the atomic structure of single molecular junctions. In this chapter, we describe the point-contact spectroscopy (PCS), inelastic electron tunneling spectroscopy (IETS), and surface-enhanced Raman scattering (SERS) as a vibration spectroscopy of single molecular junctions. Both PCS and IETS make use of electron-vibration interaction. Above a threshold voltage, the electron can excite a vibration mode of the single molecular junctions. This excitation of the vibration modes leads to an increase in differential conductance for IETS, and a decrease in differential conductance for PCS. The threshold voltage provides us with the energy of the vibration mode. In contrast with PCS and IETS, SERS does not require low temperature.
