The Emission of Circularly Polarized Radiation by Ions Following Ion-Atom and Ion Surface Collisions

D. A. Church

《Chinese Journal of Physics》 27卷2期 (1989/04) Pp. 103-116

並列摘要

Anisotropic collisions of fast ions with atoms, foils, and surfaces result in the emission of partially circularly polarized light from excited ion levels which are coherently oriented by the collision. Results from various target types are presented for low velocity (v≦0.4 a.u.) collisions leading to substantial orientations. The ion-surface grazing interaction is found to be a multiple collision resulting in an oriented core state, with the final ion state formed by capture of an electron as the ion leaves the surface. For transitions with L≠0, the isotropic core model is, however, satisfactory, leading to an analysis from which the spherical tensor parameters for excited levels are extracted. Gases adsorbed on clean surfaces lead to changes in the observed relative polarizations. There are indications that the results depend on the nature of the adsorption process. Interpretations of the data in terms of rotational coupling, the density gradient model, and capture from conduction bands and localized states are discussed.