Sub-Kelvin stereodynamics of the Ne(3P2)+N2 reaction

We present an experimental study of the low-energy stereodynamics of the Ne(3P2)+N2 reaction. Supersonic expansions of the two reactants are superposed in a merged beam experiment, where individual velocity control of the two beams allows us to reach average relative velocities of zero, yielding minimum collision energies around 60 mK. We combine the merged beam technique with the orientation of the metastable neon atoms and measure the branching between two reaction channels, Penning ionisation and associative ionisation, as a function of neon orientation and collision energy, covering the range 0.06 -- 700 K. We find that we lose the ability to orient Ne below \approx 100 K due to dynamic reorientation. Associative ionisation products, Ne-N2+, predissociate with a probability of 25% -- 35% and that associative ionisation is entirely due to reactions of the \Omega=2 state, where the singly occupied p-orbital of the Ne* is oriented along the interatomic axis.