Feshbach Resonance in NaLi-NaLi collision

Richness of molecular systems due to large number of molecular rovibrational bound states, anisotropic and long-range interactions has drawn attention for new platforms of quantum control. In recent years, new ideas emerged to explain fast losses in non-reactive molecular systems, and studies on intermediate complexes is envisioned as frontier for controlled chemistry. Feshbach resonance is one of the great tools to learn about collision complexes as they happen when a molecular bound state in the closed channel approaches the threshold of the scattering state in the open channel. ²³Na⁶Li is a fermionic molecule that has weak singlet-triplet mixing making it a suitable system to study the triplet ground state. It is notable for its both non-zero electric and magnetic dipole moments and small two-body scattering rate, as predicted by universal model for cold collision. We report our recent results on magnetic field dependent collision rate between two NaLi molecules that are highly reactive. A narrow p-wave Feshbach resonance is observed where collisional loss rate is enhanced by two orders of magnitude from the p-wave universal value at the background and approaching the 2D unitarity limit near the peak.