Spectroscopic properties and cold elastic collisions of alkaline-earth Mg + Mg+ system

In this theoretical work, we calculate molecular potential energy curves, spectroscopic constants and transition dipole moments for the ground (X-2 Sigma(+)(u), B-2 Sigma(+)(g)) and first excited electronic states (A(2)Pi(u)) of alkaline-earth molecular ion Mg-2(+). We consider an ab initio multi-reference configuration interaction method using an aug-cc-pv5z Gaussian basis set and compare our results with those obtained by others. The comparison shows a very good agreement. In addition, we investigate the ion-atom elastic collisions for a wide range of energies including the isotopic effect. In close connections, we determine the scattering T-matrix elements for ground-state electronic potentials, which show divergent behavior at a particular energy, indicating the occurrence of scattering resonances. We find that the s-wave scattering length is positive for both ground-state potentials. We also study possible free-bound transitions and Franck-Condon overlap for our system.