State-to-state chemistry at ultra-low temperature

TL;DR

This paper demonstrates high-resolution state-to-state chemistry at ultracold temperatures by preparing and analyzing reactants and products in specific quantum states, providing new insights into reaction dynamics.

Contribution

It introduces a method for quantum state-resolved investigation of chemical reactions at ultracold temperatures, enabling detailed analysis of reaction pathways and product distributions.

Findings

Recombination of ultracold Rb atoms into Rb$_2$ dimers observed.

Propensity rules for product distribution identified.

Method adaptable to other species for studying inelastic reactions.

Abstract

Fully understanding a chemical reaction on the quantum level is a long-standing goal in physics and chemistry. Experimental investigation of such state-to-state chemistry requires both the preparation of the reactants and the detection of the products in a quantum state resolved way, which has been a long term challenge. Using the high level control in the ultracold domain, we prepare a few-body quantum state of reactants and demonstrate state-to-state chemistry with unprecedented resolution. We present measurements and accompanying theoretical analysis for the recombination of three spin-polarized ultracold Rb atoms forming a weakly bound Rb$_2$ dimer. Detailed insights of the reaction process are obtained that suggest propensity rules for the distribution of reaction products. The scheme can readily be adapted to other species and opens a door to detailed investigations of inelastic or reactive processes in domains never before accessible.