Cold SO_2 molecules by Stark deceleration

TL;DR

This paper demonstrates the deceleration of SO_2 molecules to near zero velocity using a Stark decelerator with 326 stages, highlighting the importance of considering motional coupling and quantum state selectivity.

Contribution

It presents the first detailed analysis of decelerating SO_2 molecules with a large number of stages and explores motional coupling effects and quantum state selectivity.

Findings

Successful deceleration of SO_2 molecules to near zero velocity.

Identification of motional coupling as a significant factor in deceleration efficiency.

Validation of experimental results with 3D Monte-Carlo simulations.

Abstract

We produce SO_2 molecules with a centre of mass velocity near zero using a Stark decelerator. Since the initial kinetic energy of the supersonic SO_2 molecular beam is high, and the removed kinetic energy per stage is small, 326 deceleration stages are necessary to bring SO_2 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.