Excitation of Li by Fast (>10 MeV/u) N7+ and Ar18+ Projectiles

Single K-shell excitation and double-K-shell-vacancy production in atomic Li by fast N7+ (10.6 MeV/u) and Ar18+ (95 MeV/u) projectiles have been investigated. Auger electron emission, occurring in the energy range 50–100 eV and resulting from the deexcitation of singly- or doubly-K-shell excited states, respectively, was measured for various emission angles in the range 20°–160°. For incident Ar18+, high-resolution spectra were also obtained, thereby enabling the study of alignment effects for the specific Li configurations produced in the excitation process. In the case of double-K-shell-vacancy production, the two K vacancies are produced mainly by K-shell ionization plus K-shell excitation. Electron-electron effects are important in producing these latter double-K-shell-vacancy events, as well as three-electron transitions.