Polarization ratio velocity dependence dips: A collision frame model relating spectroscopic observables to the differential cross section

Abstract

We present a model that accounts for the observation described in the first paper of this series (I) of a dip in the polarization ratio profile observed in certain rotationally inelastic processes as a narrow line laser is tuned across the Doppler profile. The model is based on conservation of the projection of j along the kinematic apse [Khare, Kouri, and Hoffmann, J. Chem. Phys. 74, 2275 (1981)], a consequence of rotational angular momentum transfer in the impulsive limit. As an illustration, we present calculations of lab frame observations expected for several examples of scattering behavior in the collision frame and conclude that information on the state-to-state differential scattering cross section is contained in the polarization profile. We display a number of figures that make explicit the relationship between the relative momentum and rotational angular momentum vectors in the experiment and illustrate the ‘‘stereochemical dynamics’’ responsible for the polarization dip.