Theory of Raman scattering by molecules adsorbed on electrode surfaces

Abstract

Surface roughness and the enhanced intensity of Raman scattering by molecules adsorbed on metals

The discovery of surface-enhanced Raman scattering

“…The initial paper 6 has been cited more than 1200 times, 12 and the early papers triggered a sustained output of SERS publications, currently numbering more than 8000. 13 The main contributor to the intensity enhancement is an electromagnetic effect 14 arising from the laser excitation of localized surface plasmons (collective electron oscillations) at rough metal surfaces, which creates an enhanced electric field (E ). Both the incident and scattered light are influenced by this field enhancement, resulting in a total Raman signal enhancement proportional to E for adsorbed molecules with appropriate acceptor or donor orbitals that interact with the metal substrate.…”

Electromagnetic interactions of molecules with metal surfaces

“…In its simplest form, as originally discussed by King et al [98] and by Efrima and Metiu [99], the molecule is treated as a polarizable point spaced a distance d above a metal with local dielectric constant 62. An applied macroscopic field E 0 exp(-ioot) polarizes the molecule inducing a dipole moment~t exp (-i&0t (5.2) which also polarizes the molecule.…”

Tunable laser excitation profile of surface enhanced raman scattering from pyridine adsorbed on a copper electrode surface

“…Recent calculations based on an image field model (2)(3)(4)(5) of the surface enhancement process indicate that the Raman enhancing ability of a metal is a strong function of the frequency dependent dielectric constants of the metal and of the distance between the molecule and the image plane of the metal. According to the calculations for molecules adsorbed on copper, the interband transitions in the visible region cause suppression of the enhancement phenomenon by damping the optically driven oscillations of the conduction electrons (3,6).…”