Polarized photofluorescence excitation spectroscopy

Abstract

When a triatomic molecule ABC is photolysed by a beam of light to produce the fragments AB and C, the directional nature of the photo-dissociation process manifests itself in a number of ways; in particular, the angular distribution of each fragment is anisotropic, and the angular momentum vector J of the AB photofragment points in space with a preferential distribution with respect to the direction of the light beam. If the AB diatomic fragment is electronically excited, then the emission from AB* will, in the absence of collisions, be polarized, and a measurement of the degree of polarization, p, will provide information about the symmetry nature and dissociation dynamics of the photoexcited state (ABC)*. A number of limiting cases are presented for the sign and magnitude of p, calculated in the classical high J limit, following dissociation of both linear and bent triatomic molecules.