TARGET IONIZATION AND PROJECTILE CHARGE-CHANGING IN 0.5-8-MEV Q LIQ++HE (Q=1,2,3) COLLISIONS/

Target ionization and projectile charge changing were investigated for 0.5-8-MeV/qLi(q+)+He (q = 1,2,3) collisions. Cross sections for the s ingle and double ionization of He associated with no projectile charge change (direct ionization), single-electron capture, and single-elect ron loss were measured using coincidence techniques and compared to ex isting experimental and theoretical results. Total cross sections for single-electron capture (for Li-1,Li-2,Li-3+) and single-electron loss (for Li-1,Li-2+) mere also obtained. For a given incoming projectile charge state the double-to-single target ionization ratios R vary stro ngly with the outgoing reaction channel. For direct ionization, R is n early independent of the incident projectile charge state and can be d escribed by the semi-empirical scaling rule of Knudsen et al. [J. Phys . B 17, 3545 (1984)]. However, for ionization associated with single-e lectron loss and single-electron capture by the projectile, R depends quite strongly on the incident charge state of the projectile. These i onization ratios R are interpreted in terms of theoretical formulation s involving electron-nucleus interactions and electron-electron intera ctions.