Ultracold charged atom-dimer collisions: state-selective charge exchange and three-body recombination

TL;DR

This paper investigates ultracold charged atom-dimer collisions, revealing state-selective charge exchange and Jahn-Teller couplings that influence three-body recombination, with implications for understanding experiments in ultracold Rb systems.

Contribution

It provides a detailed analysis of potential energy surfaces and Jahn-Teller couplings in Rb$_3^+$, elucidating their role in charge exchange and three-body recombination at ultracold temperatures.

Findings

Identification of singlet and triplet surface intersections leading to Jahn-Teller couplings.

Prediction of strong state selectivity in charge exchange processes.

Explanation of three-body recombination mechanisms influenced by Jahn-Teller effects.

Abstract

Based on an accurate determination of the potential energy surfaces of Rb$_3^+$ correlated to its first asymptotic limit Rb$^+$$+$Rb($5s$)$+$Rb($5s$), we identify the presence of intersections of a pair of singlet and triplet surfaces over all interparticle distances, leading to Jahn-Teller couplings. We elaborate scenarios for charge exchange between ultracold charged atom-dimer complex (Rb$+$Rb$_2^+$ or Rb$^+$$+$Rb$_2$), predicting a strong selectivity on the preparation of the initial state of the dimer. We also demonstrate that the JT couplings must drive the three-body recombination (TBR) of Rb$^+$, Rb, and Rb at ultracold energies. Using the current analysis, we provide a consistent picture of the TBR experiments performed in ion-atom hybrid Rb samples \cite{dieterle2020inelastic,harter2012single}. We also demonstrate the presence of JT coupling as a general phenomenon in the singly-charged homonuclear alkali triatomic systems.