Resonance enhanced dynamic Rayleigh scattering

Abstract

A semiclassical theory relating the molecular resonance Rayleigh scattering intensity to the extinction coefficient of an electronic transition is presented. For isotropic molecules, the theory is shown to be equivalent to classical fluctuation theory. The semiclassical theory is then extended to include anisotropic polarizabilities. Depolarized scattering intensities and depolarization ratios are calculated for a model system, and the general features of previous experimental data are explained. Inclusion of inhomogeneous broadening in the theory predicts increased scattering intensities and decreased vibrational resolution of the scattering profile. Depolarized Rayleigh linewidths and intensity profiles are presented for a series of diphenylpolyenes, several coumarin laser dyes, and 3,4-dinitrophenol in its neutral and ionic forms. The ideal molecular properties and experimental conditions for the use of resonance enhanced dynamic Rayleigh scattering are deduced.