Isotopic Distributions in Exothermic Ion–Molecule Reactions. A Simple Model

A simple model of exothermic ion–molecule reaction is proposed in which the isotopic distribution of products is due to the separations of the center of charge from the center of mass of the diatomic reactant. Applications to the energy dependence of the isotope ratio of products of the reactions Ar + HD+ and Kr + HD+ indicate that this factor may be predominant in the energy range of 1–10 eV (center of mass).