THE ROLE OF SURFACE ELECTRONIC STATES IN SURFACE ENHANCED RAMAN-SCATTERING

The dependence of the surface enhanced Raman scattering (SERS) intensity on the electrode potential is considered in terms of the nonresonant adiabatic charge-transfer mechanism. Surface electronic states of a substrate metal are proposed to be responsible for the observed potential dependence of the SERS signal. The contribution of surface states to the nonlinear metal polarizability was found from electroreflectance spectra of silver single-crystals. Good agreement between the measured and calculated potential behavior of the SERS signal was found for pyridine absorbed on the silver electrode.