Abstract

Depolarization ratios of nonresonant Raman scattering depend on the molecular point group and the symmetry of the vibrational mode excited. When the excitation frequency approaches an electronic resonance, however, the "time" that may formally elapse between destruction of the incident photon and creation of the scattered photon may become long, and the polarization properties then depend on the rotational dynamics and relaxation pathways in the resonant electronic state as well [1]. For small isolated molecules, the rotational dynamics are often well defined, and the polarization of the emission observed with steady-state excitation can allow accurate determination of pico- and subpicosecond excited state lifetimes. This technique is essentially the light scattering analog of photofragment spectroscopy in cases where the lifetime is limited by dissociation.

© 1990 Optical Society of America