Abstract

The removal of several electrons from a diatomic molecule through photoionization is ultimately accompanied by dissociation of the atomic constituents. This phenomenon is often referred to as a “Coulomb explosion” because the atomic constituents are typically ions and it is generally believed that the asymptotic kinetic energies of the fragments are dependent solely on the Coulomb potential between them. This assumption has led some investigators to argue that dissociation of the ionized diatom originates at some distance greater than the equilibrium internuclear separation R_ℓ in order to explain the kinetic energies of the resulting atomic ions.¹ Consequently, ionization would not occur through vertical transitions. Many of the potential curves of multiply ionized diatomic molecules, however, are not represented well by Coulomb curves, especially at short range (see Fig. 1).

© 1993 Optical Society of America