Characterization of charge-exchange collisions between ultracold 6Li atoms and 40Ca+ ions

We investigate the energy dependence and the internal-state dependence of the charge-exchange collision cross sections in a mixture of ⁶Li atoms and ⁴⁰Ca⁺ ions. Deliberately excited ion micromotion is used to control collision energy of atoms and ions. The energy dependence of the charge-exchange collision cross section obeys the Langevin model in the temperature range of the current experiment, and the measured magnitude of the cross section is correlated to the internal state of the ⁴⁰Ca⁺ ions. Revealing the relationship between the charge-exchange collision cross sections and the interaction potentials is an important step toward the realization of the full quantum control of the chemical reactions at an ultralow-temperature regime.