Ionization of Ammonia Molecules by Collision with Metastable Neon Atoms

The ionization of ammonia molecules in collision with metastable neon atoms has been studied by measuring the energy spectrum of emitted electrons and the mass spectrum of product ions. The results show that nascent NH3+ ions are formed in the ground, X 2A'1, and in the first excited, A 2E, states. The latter then gives rise to dissociation leading to NH2+ ion fragments. The NH2+/NH3+ ratio is much lower than in case of Ne(I) photoionization, indicating that the particle interaction strongly influences the ionization dynamics.