Collision dynamics of excited NaK. I. Reactive KNaK and elastic HeNaK collisions

The collision dynamics of excited NaK have been studied using the technique of circularly polarised laser fluorescence. A very unusual m-dependent rate is observed for KNaK* reactive or quenching collisions which is different depending on whether the initial excitation is via Q or P, R transitions. A model is presented attributing this to the spatial distribution of the ¹Π Λ-doublet components and the influence of the nuclear function. Elastic HeNaK collisions are observed and a reorientation cross section for f = 30 was evaluated. This was found to have an upper limit of 0.3 Ų. Comparison of this with HeLi₂ reorientation cross sections indicate that the presence of a permanent dipole moment has little effect on the reorientation rate in rare gas-alkali dimer collisions.