Charge transfer of polyatomic molecules in ion-atom hybrid traps: Stereodynamics in the millikelvin regime

Rate constants for the charge transfer reaction between N${}_2$H${}^{+}$ and Rb in the mK regime are measured in an ion-atom hybrid trap and are found to be lower than the Langevin capture limit. Multireference ab initio computation of the potential energy surfaces involved in the reaction reveals that the low-temperature charge transfer is hindered by short-range features highly dependent on the collision angle and is promoted by a deformation of the molecular frame. The present study highlights the importance of polyatomic effects and of stereodynamics in cold molecular ion-neutral collisions.