Additional molecular bound states in a diabatic approach

The bound states which may result from the interaction between a discrete state and a continuum of states truncated from below are investigated in a diabatic approach for two models of a diatomic molecule. In each case the bound level can be identified as being a level allowed for by the potential energy changes resulting from the electronic configuration interaction. The various possibilities for the bound state to appear along the diabatic → Born-Oppenheimer → adiabatic → nonadiabatic chain of calculations are also discussed.