Coster-Kronig electrons from Nq+ (q = 1-3) and Oq+ (q = 1,2) Rydberg states produced in high-energy collisions with He

Coster-Kronig (C-K) electrons ejected through autoionization decay of high-Rydberg states in high-energy collisions of Nq+ (q = 1-3) and Oq+ (q = 1,2) with He have been measured with high resolution by using zero-degree electron spectroscopy. Autoionizing lines are observed corresponding to decays from 1s22p(2P)nl Rydberg states for 21 MeV N3+ + He, from 1s22s2p(3P)nl Rydberg states for 21 MeV N2+ + He and from 1s22s2p2(4P)nl Rydberg states for 14 MeV N+ + He, respectively. Angular momentum distributions of these three series of C-K decaying Rydberg states for Nq+ (q = 1-3) projectiles are also discussed, where the highly excited states are formed by single-electron excitation. Similarly, series of the autoionizing Rydberg states are observed for two charge states of incident O ions. The C-K spectra observed can be assigned to decays from 1s22s2p2(4P)nl states for 30 MeV O2+ + He and from 1s22s2p3(5S)nl states for 15 MeV O+ + He.