Inner-shell alignment of atoms in ion-atom collisions. II. Electron capture

Abstract

For pt.I see ibid., vol.13, p.1601 (1980). The alignment of ions with an inner-shell vacancy resulting from electron capture in ion-atom collisions is treated theoretically. The general expressions for the alignment are obtained in the Oppenheimer-Brinkman-Kramers and Born approximations. Simple analytical formulae for the alignment are derived within the framework of the hydrogenic model. The dependence of the degree of alignment on the incident particle velocity and the ratio of charges of the colliding particles is analysed. The alignment due to electron capture is shown to differ essentially from the alignment due to direct Coulomb ionisation. The sensitivity of the degree of alignment to the form of captured-electron wavefunctions and to the type of perturbing interaction is investigated. The experimental data on the angular distribution of Auger electrons in the ionisation of the 2p3/2subshell of Mg by protons and He+ ions are reanalysed taking into account the electron capture mechanism.