THE ROLE OF SYMMETRY IN COLLISIONS OF N2 WITH N2+

Classical trajectory methods have been used to explore the excitation of vibrations in gas-phase collisions of the nitrogen molecular ion with its parent molecule. The near symmetry of the reactants is shown to result in a high probability that the two molecules are excited by an equal amount of energy. This provides a possible explanation of the molecular beam measurements that show that the total number of vibrational energy quanta excited in the collision is, with a high probability, even.