NEAR-THRESHOLD BEHAVIOR OF THE 2P-ELECTRON EXCITATION IN MG-MG, AL-AL, AND SI-SI SYMMETRICAL COLLISIONS

Target LMM atomic Auger electron emission has been studied by low-energy ion bombardment on light-element surfaces. Our results show that the threshold energies for Mg, Al, and Si 2p core electron excitation are the same for impact of Ar+, Kr+, and Xe+ projectiles but are substantially lower for Ne+. A sensitive dependence of the energy onset on the ion incidence angle has also been observed. The intensity behavior in the near-threshold energy range is in excellent agreement with simple kinematic calculations using a binary-collision model and by taking into account only the first target-target symmetric encounters.