Collisional autoionization dynamics of Ne*–Cl2

The ionization of Cl2 molecules by collision with Ne*(3P2,0) atoms has been studied in a crossed-beam experiment in the collision energy range from 0.04 to 0.30 eV (1 eV ≈ 1.602 × 10–14 J). These processes are compared with a study of the ionization of Cl2 molecules by He I and Ne I photons performed in the same experimental conditions. The same crossed-beam apparatus has been adjusted to measure also the integral elastic cross-sections in the same collision energy range. All these experimental results show that the Ne*–Cl2 collisional processes occur with the formation of an ion-pair [Ne+⋯Cl2–] intermediate. The dynamics of this intermediate explain why the Cl+ : Cl2+ product ratio is higher than in photoionization processes.