Dependence of diatomic photofragment fluorescence polarization on triatomic predissociation lifetime

When a triatomic molecule, ABC, is dissociated by a beam of light to yield an electronically excited diatomic molecule, AB*, the degree of linear polarization of the AB* photofragment flourescence depends in general on the lifetime of the excited parent molecule, ABC*. Analytical expressions are developed for the polarization of diatomic flourescence as a function of predissociation lifetime. These calculations are carried out under the assumptions that: (a) the absorption and emission transition dipole moments can be replaced by classical hertzian dipole oscillators; (b) the AB* fragment rotates in the plane of the ABC* parent at the time of dissociation; and (c) the motion of the ABC* parent can be approximated by the classical motion of a prolate or oblate symmetric top.