Cold Molecular Collisions

MOT for cold atoms and Stark Decelerator for cold molecules

Cold atom-molecule collisions are studied in a co-trapped environment. Rubidium atoms are laser cooled before being trapped in a quadrupole magnetic trap. A cold beam of neutral ammonia molecules (ND3) or hydroxyl radicals (OH) is produced via supersonic expansion and decelerated using a Stark decelerator before being trapped in an electrostatic trap. To initiate interactions, the coils forming the magnetic trap for atoms is translated across the optical table so that the trapped samples of atoms and molecules overlap. The dynamics of the combined system is monitored by measuring the density distribution of molecules using a resonance-enhanced multi-photon ionization scheme to state-selectively ionize the molecules for subsequent detection using a multi-channel plate detector.