Studies of collision processes using light scattering

Abstract

The method of far wing collision pair spectroscopy, providing dynamical information under conditions of a half collision with control of the potential curve, the collision energy and the impact parameter range is outlined and applied to fine structure changing and depolarization mechanisms of Na3P atoms interacting with rare gas targets at thermal energies. For this purpose experimental excitation spectra of the Na3Pj find structure population ratio and J = 3/2 alignment obtained under single collision conditions [1] are analyzed on the basis of a fully quantummechanical, nonadiabatic theory of optical line shapes [2, 3] and semiclassical model calculations [4,5]. Discussed in detail are the effects on the alignment formation of molecular coherences, spin decoupling from the molecular axis, realistic trajectories and the type of transformation of molecular to atomic states during the half collision following excitation.