Formation of molecules from a Cs Bose-Einstein condensate

Conversion of an expanding Bose-Einstein condensate of Cs atoms to a molecular one with an efficiency of more than 30% was observed recently in experiments by M. Mark et al. Europhys. Lett. 69 706 (2005). The theory presented here describes the experimental results. Values of resonance strength of 8 mG and rate coefficients for atom-molecule deactivation of 1×10⁻¹¹ cm³∕s and molecule-molecule one of 1.5×10⁻⁹ cm³∕s are estimated by a fit of the theoretical results to the experimental data. Near the resonance, where the highest conversion efficiency was observed, the results demonstrate strong sensitivity to the magnetic field ripple and inhomogeneity. A conversion efficiency of about 60% is predicted by non-mean-field calculations for densities and sweep rates lower than the ones used in the experiments.