Long-range molecules

Abstract

Abstract Because of the long-range behaviour of the internuclear potential representing the interaction between two atoms (e.g. —C 6 R −6), there are usually a certain number of closely spaced vibrational-rotational levels that approach dissociation. The properties of molecules in these highest levels are quite unusual (although often simply related to the long-range forces), and we shall refer to such molecules by a special classification: ‘long-range molecules’. Restricting our attention to diatomic long-range molecules, we first review the general relationship between the potential energy curve and vibrational levels. The long-range portion of potential energy curves is examined in detail and the simple properties of vibrational levels sensitive to these long-range potentials discussed. Finally transitions (radiative, nonradiative, and collision-induced) are briefly described.