Adiabatic and non-adiabatic corrections to properties of the hydrogen molecular cation and its isotopomers: dissociation energies and bond lengths

A study is presented of adiabatic and non-adiabatic corrections to the dissociation energies and bond lengths of H⁺ ₂, D⁺ ₂ and HD⁺ in vibration-rotation levels of their ground electronic states, with particular attention to isotopic scaling. In previous work (MOSS, R. E., 1999, Molec. Phys., 97, 1) on rotationless levels, an anomalous non-adiabatic correction to the bond length was found for v = 20, N = 0 of HD⁺. Other levels close to dissociation are identified that display anomalous non-adiabatic corrections to the dissociation energies and to the bond lengths. The source of these anomalies is discussed.