Effects of the delocalized charge distribution in trapped ion-atom collisions

In the study of ion-atom interactions, the ion often remains trapped during experiments; however, the effects of the trapping potential on ion-neutral dynamics remain largely unexplored. Previous work has modeled trap-assisted ion-neutral complex formation using semiclassical theories, treating the ion as a point charge. Here, we extend this by substituting the point charge with a delocalized charged distribution according to its motional ground state in the trap. We find that the trapping frequency, which determines the spatial extent of the ion’s wavefunction, significantly alters elastic and transport cross sections in interactions with neutral atoms. Based on these findings, we propose experimental procedures to verify the effects of the delocalized charge distribution in ion-atom interactions by measuring the heating rate of the ion resulting from energy transfer in atomic collisions. This framework offers opportunities to study ion-neutral systems, providing insight into ionic polarons and trap-induced losses in hybrid experiments. The study of ion-atom interactions often requires the ion to be trapped, however the effects of the trapping potential have been elusive. The authors find that if the trapped ion is described as a delocalized charged distribution according to its motional ground state in the trap, the trap frequency modifies the scattering and transport properties of the ion in a neutral bath.