On the stereodynamics of cold and ultracold H + D₂ and D + HD chemical reactions

Stereodynamic control of rotationally inelastic scattering of ro-vibrationally excited HD molecules in cold collisions with H₂, D₂, and He has been demonstrated recently by combining co-expansion of the colliding species in a molecular beam and Stark-induced adiabatic Raman Passage techniques for the preparation of molecular states. Control of the angular distribution of the scattered molecules in these processes has also been addressed theoretically for HD + H₂, HCl + H₂ and He + HD collisions. In this work we examine the stereodynamics of H + D₂ ↔ D + HD chemical reactions with vibrational and rotational excitation of the reactants to the v = 2, 4 and j = 0-4 levels at collision energies ranging from  100 mK to 10 K.