Complete experiments in photoionization of atoms and molecules

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]