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

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.

13 pages, 16 Figures