Reactive collisions of trapped anions with ultracold atoms

TL;DR

This paper proposes a method to cool molecular anions using ultracold rubidium atoms, studies associative detachment losses, and measures ion density distributions to understand collisional cooling processes.

Contribution

It introduces a scheme for embedding molecular anions in ultracold atoms and provides experimental measurements of loss rates and ion distributions.

Findings

Measured absolute rate coefficients for associative detachment.

Identified conditions for effective translational and internal cooling.

Demonstrated the feasibility of collisional cooling of molecular ions.

Abstract

We present a scheme to embed molecular anions in a gas of ultracold rubidium atoms as a route towards the preparation of cold molecular ions by collisional cooling with ultracold atoms. Associative detachment as an important loss process in collisions between OH- molecules and rubidium atoms is studied. The density distribution of trapped negative ions in the multipole radiofrequency trap is measured by photodetachment tomography, which allows us to derive absolute rate coefficients for the process. We define a regime where translational and internal cooling of molecular ions embedded into the ultracold atomic cloud can be achieved.