Cold N+NH Collisions in a Magnetic Trap

Abstract

We present an experimental and theoretical study of atom-molecule collisions in a mixture of cold, trapped atomic nitrogen and NH molecules at a temperature of $\sim 600$~mK. We measure a small N+NH trap loss rate coefficient of $k_{\mathrm{loss}}^{(\mathrm{N}+\mathrm{NH})}=8(4)\times 10^{-13}$~cm${}^3$s${}^{-1}$. Accurate quantum scattering calculations based on {\it 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+NH elastic to inelastic collisions remains large ($>100$) into the mK regime.