The angular distribution of Auger electrons in the decay of resonantly excited atomic states is studied theoretically. The two-step model is used for B description of the Auger process with the excited electron as a spectator. Expressions for the angular anisotropy parameters in the jK and jj coupling schemes are obtained for excitation of a closed-shell system. A close relation between the angular anisotropies of the resonant Auger and normal Auger processes is found within the framework of the spectator model.Numerical calculations for resonant Auger transitions in Ar, Kt and Xe are presented and compared with recent experiments.

4.6, Wcloria 3052, Austr;ilia t Fnlz-Haber-Institut der Max-Planck-Gesellschaft, D-14195 Berlin. Federal Republic of -Y

Elastic collisions between initially unpolarized electrons and hydrogenlike atoms are discussed, aiming to analyze the entanglement properties of the correlated final spin system. Explicit spin-dependent interactions are neglected and electron exchange only is taken into account. We show the final spin system to be completely characterized by a single spin correlation parameter depending on scattering angle and energy. Its numerical value identifies the final spins of the collision partners to be either in the separable, entangled, or Bell correlated regions. We emphasize explicit examples for the mixed spin system in order to illustrate the abstract concepts. The analysis of published experimental and numerical data reveals the possibility to create tunable pairs of collision partners with any desired degree of spin entanglement.

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A general theory is developed for the angular distribution of Auger electrons emitted in the decay of molecular vacancies created by electron impact. The molecules are assumed as freely rotating. General expressions are derived where the angular distribution of the emitted Auger electrons is related to the anisotropy of the molecular axis distribution and to the shape and spatial orientation of the electronic orbitals prior to the Auger emission. Particular emphasis is placed on the correct formulation of the coherences produced during the ionization which requires an extension of previously derived formulas. The obtained equations are a necessary first step for future numerical calculations.