Theoretical investigation of the long-lived metastable AlO2+ dication in gas phase

•Theoretical investigation of gas-phase molecular species AlO2+.•Spectroscopic parameters of this dication in its electronic ground and exited states.•Theoretical double ionization spectrum of AlO.

We report the results of a detailed theoretical study of the electronic ground and excited states of the gas-phase doubly charged ion AlO2+ using high-level ab initio computer calculations. Both standard and explicitly correlated methods were used to calculate their potential energy curves and spectroscopic parameters. These computations show that the ground state of AlO2+ is X2Π. The internuclear equilibrium distance of AlO2+(X2Π) is computed 1.725 Å. We also deduced the adiabatic double ionization and charge stripping energies of AlO to be about 27.45 eV and 17.80 eV, respectively.