Variation of the polarization ratio for rotationally inelastic collisions with laser selected velocity

We extend the technique of velocity selection by narrow linewidth laser excitation by measuring the polarization of emission following energy transfer as a function of selected velocity. We apply this to rotationally inelastic collisions in A1ΣuLi2–Xe and find that for most transitions, there is a noticeable decrease in the circular polarization ratio at the center of the Doppler profile. We speculate as to whether the reason for this is dynamical, geometrical, or a combination of the two. We are able to deconvolute cross sections for the transfer of orientation as a function of relative speed which can then be compared with cross sections for the transfer of population.