Toward Control of Collisions between Ultracold Triplet Ground State NaLi Molecule and Na Atom

There have been extensive efforts in understanding molecular collisions in the quantum regime. As the colliding bodies get heavier, due to the high rovibrational density-of-states of the collision complex, theoretical simulation of collisions becomes challenging and experimental observation of resolvable scattering resonances is predicted to be difficult. Utracold NaLi -- the lightest bi-alkali molecule -- that lives long in the triplet manifold of the electronic spin offers a new platform for the study of atom-molecule and molecule-molecule collisions, as a benchmark system for theoretical quantum scattering calculations. We report progress on magnetic control of collisions between the triplet ground state NaLi molecules and Na atoms, building from a recent result on internal state control of colliding particles. This can help improve the efficiency of sympathetic cooling of a spin-polarized NaLi-Na mixture at ultracold temperature, which has been recently demonstrated, and in understanding the short-range physics and the three-body potential energy surface.