抄録
Highly Surface-enhanced Raman Scattering (SERS) active Ag dimer array was prepared to investigate the orientation of molecules in an anisotropic electromagnetic field. The system allow us to observe very clear time-dependent change in the SERS spectra of 4,4'-bipyridine adsorbed in water. The SERS spectra showed several characteristic features especially in the change of relative intensity of the bands. The characteristics were compared with those of the calculated Raman spectra with distinct irradiation polarization. The analysis indicates that the spectra reflect the orientation of molecules. The 2D cross correlation analysis further prove that the present observation provide the information on the dynamics of a small number of molecules in the highly localized anisotropic electromagnetic field at the nano-gap of the Ag dimer
