Cold N + NH Collisions in a Magnetic Trap

We present an experimental and theoretical study of atom-molecule collisions in a mixture of cold, trapped N atoms and NH molecules at a temperature of 600 mK. We measure a small N þ NH trap loss rate coefficient of kðNþNHÞ loss ¼ 9ð5Þð3Þ 1013 cm3 s1. Accurate quantum scattering calculations based on ab initio interaction potentials are in agreement with experiment and indicate the magnetic dipole interaction to be the dominant loss mechanism. Our theory further indicates the ratio of N þ NH elasticto-inelastic collisions remains large (> 100) into the mK regime.Physic