The ZnO2+ dication in the gas phase

Our high-level ab initio calculations show that the ZnO2+ electronic ground state of 3Σ− symmetry is metastable with a bond length of 2.066 Å, an effective dissociation energy of 1.42 eV, and a double ionization energy of ZnO of 26.61 eV. Spectroscopic constants, adiabatic excitation energies, tunneling and spin–orbit induced predissociation lifetimes for the vibrational levels in the low-lying electronic states of ZnO2+ were determined and the metastability of the dication was discussed. For the lower electronic states of ZnOn+ (n = 0, 1, 2) species, the spectroscopic characteristics of the Λ–S states were calculated and the double ionization spectrum of ZnO was simulated.