On the metastability of doubly charged homonuclear diatomics

Generalized valence bond (GVB) and spin-coupled (SC) calculations were used in conjunction with the generalized product function energy partitioning (GPF-EP) method to describe the origin of metastability in doubly charged homonuclear dications. A model to describe the formation of metastable potential wells based on interference and quasi-classical effects is presented. The GPF-EP picture of dications is the result of polarization-aided strong covalent bonding surpassing Coulomb electrostatic repulsion. Important differences in the quasi-classical density profiles of He22+ and Ne22+ reveal the underlying mechanism that could lead to bound or unbound states. Finally, the nature of the chemical bond of N22+, O22+, and F22+ is described. The results suggest that the ground states of the mentioned dications are bounded and that the depth of the potential wells of these exotic species is related to the interference effect, in the same way as in previously studied neutral molecules.