N₂ dissociative ionization by electron impact

Dissociative single, double and triple ionization of N₂ induced by 200, 400 and 1000 eV electron impact are studied using the cold target recoil-ion momentum spectroscopy (COLTRIMS) technique. Kinetic energy releases (KERs) are determined for dissociation channels (N₂ ⁺ → N⁺ + N, N₂ ²⁺ → N²⁺ + N) and Coulomb explosion channels (N₂ ²⁺ → N⁺ + N⁺, N₂ ³⁺ → N²⁺ + N⁺). It is observed that as the electron-impact energy increasing, different channels behave quite differently. Through analyzing the electronic states of the precursor molecular ion in each channel, the present KER measurements show that ionization from different valance orbitals plays a very important role in the dissociation of molecules.