Laser-cooling molecules - Concept, candidates, and supporting hyperfine-resolved measurements of rotational lines in the A-X(0,0) band of CaH

摘要

Certain molecules, it seems, may be laser cooled by methods technically similar to those applied with abundant success in atomic. physics. We discuss the spectroscopic criteria molecules should meet to make methods of Doppler cooling technically feasible and identify diatomic candidates. Some candidates, such as the alkaline-earth monohydrides (e.g. BeH and CaH), are paramagnetic and amenable to magneto-optical trapping. Our experimental study concentrates on CaH, and we present our recent high-resolution, molecular-beam-based measurements of low-J rotational lines within the A-X (0,0) band of CaH. From these measurements we report hyperfine separations in the A-state, as important to laser-cooling spectroscopy, and centroidal transition frequencies for comparison with existing values. We conclude with an outline of a possible magneto-optical trap for CaH.