Ultracold RbSr molecules can be formed by magnetoassociation

TL;DR

This paper explores the formation of ultracold RbSr molecules via magnetoassociation, highlighting the role of magnetic field tuning and previously overlooked Hamiltonian terms in producing Feshbach resonances for molecule creation.

Contribution

It introduces the potential for forming paramagnetic polar molecules from Rb and Sr atoms by identifying key resonance mechanisms and the effects of hyperfine interactions.

Findings

Presence of tunable molecular bound states near atomic thresholds

Identification of zero-energy Feshbach resonances with significant widths

Hyperfine interaction variations significantly influence resonance behavior

Abstract

We investigate the interactions between ultracold alkali metal atoms and closed-shell atoms using electronic structure calculations on the prototype system Rb+Sr. There are molecular bound states that can be tuned across atomic thresholds with magnetic field, and there are previously neglected terms in the collision Hamiltonian that can produce zero-energy Feshbach resonances with significant widths. The largest effect comes from the interaction-induced variation of the Rb hyperfine coupling. The resonances may be used to form paramagnetic polar molecules if the magnetic field can be controlled precisely enough.