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The polarization vector P of scattered electrons interacting with a polarized target electrons is compared with the entanglement (or non-separability) of the electron states of the interacting electron pair. The separability S is defined as a linear function of the von Neumann entropy. The shapes of the functions P ( θ , Ω , φ ) and S ( θ , Ω , φ ) are similar and simultaneously achieve their maximum value at the scattering angle θ values close to 0 and π and simultaneously tend to zero in the case of symmetric scattering at θ ≈ π /2. In the latter case the scattered electrons are described by an asymmetric spin part of the wave function, which by definition corresponds to the spin entangled ( S ≈ 0) electron states of the interacting electron pair. Comparison of the model calculation results with experimental results of the spin polarized electron spectroscopy of the ferromagnetic solid shows qualitative agreement. The analytical expression relating polarization and separability of the two interacting particles enables use the measured polarization of scattered electrons for estimation of the spin-entanglement or separability of the two particle systems. [ABSTRACT FROM AUTHOR]

Abstract: The general discussion of possible complete experiments in photoionization of atoms and molecules is presented. In atoms the complete experiment must include measurements of the angular distribution and spin polarization of photoelectrons and the alignment or/and orientation of the residual ion. Two relations connecting the spin polarization parameters and the parameters characterizing the ion polarization state are presented. The complete experiments performed for Xe atom demonstrated a good agreement between theory and experiment. The complete experiments in photoionization of diatomic molecules can be performed by measuring photoelectron angular distributions for fixed-in-space molecules with circularly or elliptically polarized light. The use of additional experimental data like the angular asymmetry parameter and the ratio of to symmetry resolved cross sections made it possible to extract as many as 16 dipole matrix elements and phase shift differences for the C K-shell of CO molecule. Comparison with the recent calculations in the relaxed core Hartree–Fock approximation revealed discrepancies between theory and experiment. [Copyright &y& Elsevier]

Photoelectron diffraction (PED) effects in magnetic solids are described within a one-electron non-relativistic model. The theory presented permits a straightforward calculation of spin-resolved PED patterns, whereby different spin arrangements in a magnetic solid may be considered. Both spin–orbit interaction and exchange interaction with the spin-polarized valence band have been taken into account in the description of the initial core state. The multiple scattering of the excited photoelectron wave is treated within a multiple-scattering cluster model. The theory may be applied to explain PED effects in magnetic solids in comparison to the nonmagnetic case. [Copyright &y& Elsevier]