Shielding $^2\Sigma$ ultracold dipolar molecular collisions with electric fields

TL;DR

This paper demonstrates that applying strong electric fields to $^2\Sigma$ ultracold dipolar molecules induces long-range repulsion, significantly reducing inelastic collisions and chemical reactions, thus enhancing their stability for experimental applications.

Contribution

It shows that electric fields can effectively shield $^2\Sigma$ molecules from inelastic collisions, with specific analysis on molecules like RbSr, SrF, BaF, and YO, highlighting the role of electronic and nuclear spins.

Findings

Orders of magnitude suppression in quenching rates.

Effective long-range repulsion above a critical electric field.

Electronic and nuclear spins act as spectators in shielding.

Abstract

The prospects for shielding ultracold, paramagnetic, dipolar molecules from inelastic and chemical collisions are investigated. Molecules placed in their first rotationally excited states are found to exhibit effective long-range repulsion for applied electric fields above a certain critical value, as previously shown for non-paramagnetic molecules. This repulsion can safely allow the molecules to scatter while reducing the risk of inelastic or chemically reactive collisions. Several molecular species of $^2\Sigma$ molecules of experimental interest -- RbSr, SrF, BaF, and YO -- are considered, and all are shown to exhibit orders of magnitude suppression in quenching rates in a sufficiently strong laboratory electric field. It is further shown that, for these molecules described by Hund's coupling case b, electronic and nuclear spins play the role of spectator with respect to the shielding.