Cold collisions of aligned D₂ molecules

It has recently become experimentally possible to study inelastic collisions between two aligned D₂ molecules at around 1 K. Such collisions between aligned molecules in the cold regime allow for the detailed interrogation and control of bimolecular collisions. Here, I discuss the theoretical formalism for collisions of aligned molecules, and apply the approach to state-prepared D₂. Based on full-dimensional quantum scattering calculations, on an accurate H₂-H₂ interaction potential, the experimental angular distributions are reproduced for different initial alignments. An analysis of the angular distribution reveals that the key features could primarily be attributed to a partial wave resonance with orbital angular momentum l=4.