Collision Induced Dissociation of Molecular Ions

Velocity vector distributions of the fragment ion products of the dissociative collisions of O2+, N2+, NO+, and N2O+ with He have been determined, using projectile-target relative kinetic energies which are one to three times the bond energy of the molecular ion. The most probable dissociation event produces a fragment ion whose velocity is very nearly the same as that of the original projectile ion. Fragment ions also appear at smaller velocities and larger scattering angles, and the importance of these features increase with increasing initial relative energy. Three models for the dissociation are discussed, and it is concluded that a version of the stripping model is most nearly consistent with the data.