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Abstract

In this paper, we initially list 23 subfields of the research topics associated with the title of this paper. Then we present a detailed theoretical description of polarized–electron interactions with atoms and molecules. Spin effects based on Coulomb–direct, Coulomb–exchange and spin–orbit interactions in light and heavy atoms are described, and experimental data are presented as tests for relevant theoretical approximations. Electron–scattering interactions with orientated molecules such as CH₃I and CH₃Cl show interesting alignment and orientation effects, which are new types of test quantities for the theory of such electron–scattering processes with molecules. Numerous multielectron effects determine photoionization of atoms in general. Spin and spin–orbit interaction effects particularly can be studied by photoelectron spin experiments and by applying polarized atoms in the photoionization process. The former type of experiment has been used very successfully in the photoionization of rare gas atoms, while the latter type of experiment and related theories have been applied particularly for photoionization with partly filled subshells. Out of such photoionization experiments with polarized atoms we selected the one with oxygen atoms {O(1s²2s²2p⁴) ³P₂+hν} for a more detailed description. While the photoionization process with unpolarized oxygen atoms is characterized by the cross–section, σ, and the angular distribution, β, only; a further parameter, β′, is required for photoionization with polarized oxygen atoms. Alternatively, it is possible to describe the photoionization of polarized oxygen atoms by deriving β and β′ from the ratio of two reduced matrix elements for s and d electrons and their relative phase difference.