Universal stereodynamics of cold atom-molecule collisions in electric fields

TL;DR

This study demonstrates that cold atom-molecule collisions exhibit universal stereoselectivity influenced by electric fields, with the ability to control inelastic scattering through field-induced resonances, revealing fundamental collision dynamics.

Contribution

The paper introduces a universal quantum dynamical framework showing stereoselectivity in cold atom-molecule collisions influenced by electric fields, including control via resonances.

Findings

Inelastic scattering is highly dependent on molecular orientation in electric fields.

Universal stereoselectivity arises from threshold suppression of certain Stark sublevels.

Electric-field-induced resonances enable control of collision outcomes.

Abstract

We use numerically exact quantum dynamics calculations to demonstrate universal stereoselectivity of cold collisions of $^2\Pi$ molecules with $^1$S-state atoms in an external electric field. We show that cold collisions of OH molecules in their low-field-seeking $f$ states, whose dipole moments are oriented against the field direction, are much more likely to lead to inelastic scattering than those of molecules oriented along the field direction, causing nearly perfect steric asymmetry in the inelastic collision cross sections. The universal nature of this effect is due to the threshold suppression of inelastic scattering between the degenerate $\pm M$ Stark sublevels of the high-field-seeking $e$-state, where $M$ is the projection of the total angular momentum of the molecule on the field axis. Above the $\Lambda$-doublet threshold, the stereodynamics of inelastic atom-molecule collisions can be tuned via electric-field-induced resonances, which enable effective control of Ne + OH scattering over the range of collision energies achievable in current merged beam experiments.