Coster-Kronig electrons from N^q+ (q1-3) and O^q+ (q1,2) 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 N^q+ (q 1-3) and O ^q+ (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 N^q+ (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 1s ²2s2p²(⁴P)nl states for 30 MeV O²⁺ + He and from 1s²2s2p³(⁵S)nl states for 15 MeV O⁺ + He.