Bond formation between positively charged species. Non-adiabatic analysis and valence-bond model in the CO2+ case

Ab initio MCSCF calculations of the potential energy curves of the first low-lying states of the CO2+ dication have been performed. A localization procedure of MCSCF orbitals allows us to discuss the bond formation in the framework of valence-bond theory. The non-adiabatic curves corresponding to C+ + O+, C2+ + O and C + O2+ are described using both orthogonal and non-orthogonal quasi-atomic orbitals, allowing us to re-examine the currently proposed models of bond formation between positively charged species.