Velocity-space pictures of continuum electrons produced by slow, bare, highly charged ions

Velocity-space pictures of the electron continua produced by the impact of ions on He and Ne have been measured for the bare projectiles of p, He, C, O, and Ne at a projectile velocity of 1.63 a.u. For the three highly charged projectiles, this velocity lies in the ionization {open_quotes}threshold{close_quotes} region where electron capture dominates the reaction. The electron velocity-space distributions for these cases are concentrated near the velocity of the projectile, not near the saddle-point velocity, and seem to {open_quotes}saturate{close_quotes} at a nearly universal shape. The data are in qualitative agreement with CDW-EIS calculations. {copyright} {ital 1997} {ital The American Physical Society}