Unified Treatment of Fluorescence and Raman Scattering Processes near Metal Surfaces

We present a general model study of surface-enhanced resonant Raman scattering and fluorescence focusing on the interplay between electromagnetic effects and the molecular dynamics. Our model molecule is placed close to two Ag nanoparticles and has two electronic levels. A Franck-Condon mechanism provides electron-vibration coupling. Using realistic parameter values for the molecule we find that an electromagnetic enhancement by 10 orders of magnitude can yield Raman cross sections ${\sigma }_R$ of the order ${10}^{-14}{\mathrm{c}\mathrm{m}}^2$. We also discuss the dependence of ${\sigma }_R$ on incident laser intensity.