The role of asymptotic vibrational states in H D 3

Calculations are discussed which characterize all the vibrational bound states of the H3 and D2H C molecular ions using a realistic ab initio potential energy surface. Graphical analysis and calculation of rotational constants show that both ions support a series of atom–diatom-like long-range states: asymptotic vibrational states. The role of these states in the H3 system and other molecules is discussed. The vibrational calculations are extended above dissociation where the resulting (Feshbach) resonances are shown to be too short-lived to be of importance for the H3 photodissociation spectrum.