Cold SO2 molecules by Stark deceleration

Abstract.We produce SO2 molecules with a centre of mass velocity near zero using a Stark decelerator. Since the initial kinetic energy of the supersonic SO2 molecular beam is high, and the removed kinetic energy per stage is small, 326 deceleration stages are necessary to bring SO2 to a complete standstill, significantly more than in other experiments. We show that in such a decelerator possible loss due to coupling between the motional degrees of freedom must be considered. Experimental results are compared with 3D Monte-Carlo simulations and the quantum state selectivity of the Stark decelerator is demonstrated.