Long-term trapping of Stark-decelerated molecules

Trapped cold molecules represent attractive systems for precision-spectroscopic studies and for investigations of cold collisions and chemical reactions. However, achieving their confinement for sufficiently long timescales remains a challenge. Here, we report the long-term trapping of Stark-decelerated OH radicals in their X 2Π3/2 (ν = 0, J = 3/2, MJ = 3/2, f) state in a permanent magnetic trap. The trap environment is cryogenically cooled to a temperature of 17 K to suppress black-body-radiation-induced pumping of the molecules out of trappable quantum states and collisions with residual background gas molecules which usually limit the trap lifetime. The cold molecules are thus confined on timescales approaching minutes, an improvement of up to two orders of magnitude compared with room temperature experiments, at translational temperatures of ∼25 mK. The present results pave the way for new experiments using trapped cold molecules in precision spectroscopy, in studies of slow chemical processes at low energies and in the quantum technologies. Prospects for new applications in quantum simulations, spectroscopic precision measurements and very low temperature physics and chemistry have resulted in significant advances in the study of cold molecules, with their trapping for long times remaining a major challenge. The authors present an experiment in which polar molecular radicals produced by Stark deceleration are magnetically trapped for a time of order 20 s providing an improvement of up to two orders of magnitude over room temperature experiments.