Cold heteronuclear atom-ion collisions

TL;DR

This paper investigates cold heteronuclear atom-ion collisions by measuring elastic and inelastic collision rates at ultracold temperatures, revealing quantum effects and reaction pathways with single-particle resolution.

Contribution

It provides the first detailed quantum-mechanical analysis of energy-dependent elastic and inelastic atom-ion collisions at ultracold temperatures, including reaction product identification.

Findings

Elastic collision rates deviate from Langevin predictions

Quantum mechanical cross sections accurately describe elastic scattering

Reaction pathways and branching ratios are characterized at the single-particle level

Abstract

We study cold heteronuclear atom ion collisions by immersing a trapped single ion into an ultracold atomic cloud. Using ultracold atoms as reaction targets, our measurement is sensitive to elastic collisions with extremely small energy transfer. The observed energy-dependent elastic atom-ion scattering rate deviates significantly from the prediction of Langevin but is in full agreement with the quantum mechanical cross section. Additionally, we characterize inelastic collisions leading to chemical reactions at the single particle level and measure the energy-dependent reaction rate constants. The reaction products are identified by in-trap mass spectrometry, revealing the branching ratio between radiative and non-radiative charge exchange processes.