N (2P) production in electron-N2 collisions

A unique detector which is selectively sensitive to low energy metastable atoms, has been used to study the production of ground state N (2P) atoms following collisions of low energy (0-200 eV) electrons with molecular nitrogen. Time-of-flight techniques have revealed the existence of at least two distinct mechanisms yielding this dissociation product. Released kinetic energies in the dissociation have allowed positioning of the parent molecular states in the Franck-Condon region. This, together with excitation probability curves, has allowed probable parent states, such as B′ u − 3 , b′ u + 1 and C′ 3 u, to be identified making use of recent theoretical calculations. Both direct and pre-dissociation processes are shown to be involved.