Screening and antiscreening in the semiclassical description of ionization in fast ion-atom collisions

Abstract

Impact parameter dependence of the ionization probability in fast ion-atom collisions is theoretically studied. A role of projectile ion electrons in the ionizing collisions (or, equivalently, of target electrons in the electron loss process) is discussed. Within the framework of the first-order semiclassical approximation a method is suggested allowing inclusion of double electron excitations in the calculation. Using this method the screening and antiscreening effects of various values of impact parameter are quantitatively studied. The effective charge of the ion as a function of the impact parameter is introduced. It is shown that the effective charges for the ionization probability and for the mean energy transfer are different and have different dependence on the impact parameter.

Impact-parameter dependence for collisions of atoms with projectiles carrying electrons

“…The impact-parameter representation has been discussed recently by Montenegro and Meyerhof [17,18], Ricz et al [19], and Kabachnik [20]. Our paper develops the first-order theory in the impact-parameter representation for both screening and 1050-2947/95/51(1)/504(9)/$06.…”

Cold Target Recoil Ion Momentum Spectroscopy

“…In both cases the recoil ion momentum is smeared out by the momentum transfer caused by the target ionization. In addition to the di!erence in k , one expects larger k , for the (ne) than for the (ee) mechanism, since for the (ne) mechanism the impact parameter between the nuclei needs to be in the range of the projectile electron shell radius [206,207,209,210] and thus smaller than for the (ee) process. Fig.…”

Coulomb excitation of highly charged projectile ions in relativistic collisions with diatomic molecules

“…II A and II B for the simplest case of hydrogen-like incident ions. Here we introduce, in particular, the bound-state transition amplitudes that are evaluated within the wellestablished semiclassical approximation [20][21][22], in which the projectile is assumed to move with constant velocity along a straight-line trajectory. Later, in Sec.…”