Excitation of Li by fast (> 10 MeV/u) N7+ and Ar18+ projectiles

Single K-shell excitation and double-K-shell-vacancy production in atomic L i by fast N7+ (10.6 MeV/u) and Ar18+ (95 MeV/u) projectiles have been inves tigated. Auger electron emission, occurring in the energy range 50-100 eV a nd resulting from the deexcitation of singly- or doubly-g-shell excited sta tes, respectively, was measured for various emission angles in the range 20 degrees-160 degrees. 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 doubl e-K-shell-vacancy production, the two K vacancies are produced mainly by K- shell ionization plus K-shell excitation. Electron-electron effects are imp ortant in producing these latter double-K-shell-vacancy events, as well as three-electron transitions.