Rotational state-changing collisions between N$_2^+$ and Rb at low energies

TL;DR

This study provides a quantum-mechanical analysis of rotational collisions between N$_2^+$ ions and Rb atoms at very low temperatures, showing inelastic processes are minor compared to charge exchange in hybrid traps.

Contribution

It offers the first detailed quantum-scattering calculations of rotational inelastic collisions for N$_2^+$ and Rb at sub-Kelvin temperatures, highlighting their relative insignificance.

Findings

Rotational inelastic collision rates are at least ten times smaller than charge-exchange rates.

Inelastic processes are minor channels in typical hybrid trapping conditions.

Quantum-scattering calculations on ab-initio potentials were used to determine cross sections.

Abstract

We present a theoretical study of rotationally elastic and inelastic collisions between molecular nitrogen ions and Rb atoms in the sub-Kelvin temperature regime prevalent in ion-atom hybrid trapping experiments. The cross sections for rotational excitation and de-excitation collisions were calculated using quantum-scattering methods on ab-initio potential energy surfaces for the energetically lowest singlet electronic channel of the system. We find that the rotationally inelastic collision rates are at least an order of magnitude smaller than the charge-exchange rates found in this system, rendering inelastic processes a minor channel under the conditions of typical hybrid trapping experiments.