Unified treatment of fluorescence and Raman scattering processes near metal surfaces

TL;DR

This paper develops a comprehensive model for surface-enhanced Raman scattering and fluorescence near metal surfaces, highlighting electromagnetic and molecular interactions, with significant enhancement factors demonstrated.

Contribution

It introduces a unified theoretical framework for both fluorescence and Raman processes near metal nanoparticles, incorporating electromagnetic effects and molecular dynamics.

Findings

Electromagnetic enhancement can reach 10 orders of magnitude.

Raman cross-sections can be as high as 10^{-14} cm^2.

Dependence of Raman signal on laser intensity is analyzed.

Abstract

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 $10^{-14} \unit{cm^2}$. We also discuss the dependence of $\sigma_{R}$ on incident laser intensity.