Cold collisions between alkali metals and alkaline-earth metals in the heteronuclear atom-ion system Li plus Ba

In a recent experiment [P. Weckesser et al., Nature (London) 600, 429 (2021)], the quantum s-wave regime was attained for an alkali-metal and alkaline-earth atom-ion combination (LiBa+). We investigate possible outcomes from the interaction of this ion-atom pair at quantum regimes from a theoretical point of view. For this purpose, Born-Oppenheimer potential energy surfaces are constructed for the three lowest dissociation channels of the (Ba-Li)+ molecular system using a multireference configuration interaction electronic-structure calculation. We present elastic, spin-exchange (SE), and diffusion cross sections in different energy regimes. The collisional properties of this system are calculated in terms of the scattering phase shifts and scattering cross sections, and the semiclassical behavior at a relatively high energy limit is also examined. For SE collisions, phase locking is obtained towards lower partial waves.