Unified description of circular polarization in supermultiplet lines of ions, excited by beam surface interaction

Abstract

The excitation process of energetic ions, reflected at grazing angles from a metallic target, is assumed to be an electron-loss-capture-sequence. The density operator at the time of the last capture is factorized into an anisotropic part for the optical electron and an isotropic part for the inner electrons. Parentage approximation and LS-coupling then give the orientation for all levels of a supermultiplet. The circular polarized light, emitted during transitions from these levels, can be well fitted, with exception of lines from L = 0 terms. This shortcoming is removed by an extended model. This suggests that the parent ions, too, are oriented.

Theory of optical polarization due to electron capture from localized target states by fast ions

“…This fact and the reflection symmetry of the target state (19) leads to S=0 since the imaginary part of (18) vanishes as a result of the qr integration of (15). We notice that S = 0 is still true if the reflection symmetry of the target state does not hold, but if the projectile potential can be treated in the central-field approximation.…”

“…(5) can be replaced by the capture matrix (3). In doing this we have also ignored possible post-collision effects due to cascades or external field effects, which are, however, of minor importance for the production of atomic orientation in non-hydrogenic projectiles [19,20].…”

“…To be more specific, the calculation reproduces the experimental results for the line ArlI 4s2Ds/2-4p2FT/2 at v=v o [31]: S/I=0.8, M/I=O.04 and C/I =0.0 within the experimental error. Deviating from our basic assumption on this point, an isotropic spins= 1/2 and an isotropic singlet O core have been taken into account for the resulting polarization of the s2Ds/2-p2FT/2 multiplet line (for details, see [19]). An analogous calculation for capture into 3p-states yields similar results confirming the assumption of only a weak dependence of the polarization on the principal quantum number of the final state.…”