SATURATION EFFECTS IN PROJECTILE ELECTRON LOSS

The behavior of the projectile electron-loss cross sections with the t arget atomic number, Z(2), presents a saturation as the value of Z(2) increases. This fact, which had already been observed for the excitati on of highly charged projectiles, appears in the first-order calculati ons for the contribution of the projectile electron-target electron in teraction but not for the projectile electron-target nucleus interacti on. In this work, we compare total electron-loss cross sections with E lectron Loss to the Continuum (ELC) yields, for 1.0 MeV He+ projectile on various targets, with atomic numbers ranging from 2 to 54. Besides a similar saturation with Z(2) observed in both cases, some differenc es between the data appear, such as enhanced values of the total loss for all targets when compared to the ELC and a structure between the A r and Xe targets also in the total loss data. These differences may be assigned to the contribution due to the interaction between the proje ctile active electron and the target electron cloud. (C) 1997 Elsevier Science B.V.