Surface-Enhanced Raman Spectroscopy and Surface Plasmons

Abstract
The Raman spectra of 4-pyridine-carboxaldehyde-doped Al-Al2 O3-Ag tunnel junctions evaporated onto CaF2 films and optical diffraction gratings show that the molecular Raman scattering is strongly enhanced under conditions which permit the direct excitation of the surface plasmon modes of Ag. This suggests that the surface plasmon is an intermediate state in surface-enhanced Raman scattering.