Charge-state dependence of very low projectile autoionizing transitions from 2 MeV/u Sq+ + He collisions

Abstract

Charge-state dependence for low energy projectile autoionizing transitions from 2 MeV/u Sq+ (q = 6, 11 to 13) ions on He and C-foil targets was measured using a zero-degree electron spectrometer. A series of autoionization electrons produced by the Coster-Kronig transitions of 1s22p(2P3/2)9l-1s22sϵl' are identified in the electron energy range up to 2.5 eV for the S12+ + He collision. No characteristic lines are observed in the electron energy spectra following the S13+ ion beam excitation with He. This indicates that electron excitation and capture processes that could produce the Li- and Be-like initial configurations resulting in autoionizing Coster-Kronig transitions do not occur during collisions between S13+ ions and a He target at this collision energy. It is suggested that the electron spectra for the S11+ projectiles show a series of autoionizing Coster-Kronig transitions of 1s22p27l-1s22s2pϵl', 1s22p29l-1s22s2pϵl' and 1s22s2p9l-1s22s2ϵl' for S11+ ions, in addition to 1s22p(2P3/2)9l-1s22sϵl' transitions for S12+ ions.