Enhanced Raman Scattering by Adsorbates Including the Nonlocal Response of the Metal and the Excitation of Nonradiative Modes

Abstract

The enhanced Raman scattering from a molecule adsorbed on a metal surface is calculated by use of classical electrodynamics. The metal response function is modeled with a local interband term plus a nonlocal free-electron term. The important effects are the image enhancement of the effective dipole and the roughness coupling of the near fields of the dipole and its image. These combine to give estimated gains ≈ ${10}^6$.