Interactions and low energy collisions between an alkali ion and an alkali atom of different nucleus

Abstract: We study theoretically interaction potentials and low energy collisions between different alkali atoms and alkali ions. Specifically, we consider systems like X + Y$^{+}$, where X(Y$^{+})$ is either Li(Cs$^+$) or Cs(Li$^+$), Na(Cs$^+$) or Cs(Na$^+$) and Li(Rb$^+$) or Rb(Li$^+$). We calculate the molecular potentials of the ground and first two excited states of these three systems using pseudopotential method and compare our results with those obtained by others. We derive ground-state scattering wave functions and analyze cold collisional properties of these systems for a wide range of energies. We find that, in order to get convergent results for the total scattering cross sections for energies of the order 1 K, one needs to take into account at least 60 partial waves. Low energy scattering properties calculated in this paper may serve as a precursor for experimental exploration of quantum collisions between an alkali atom and an alkali ion of different nucleus.