Gomonai H. Resonance and autoionizing phenomena in the processes of electron collisions with metal atoms

Using spectroscopic technique in crossed monoenergetic electron and ion beams, the resonance and autoionizing phenomena at the electron interactions with many-electron Zn+, Cd+, In+ and Tl+ ions (i.e. excitation, recombination and ioniza-tion with excitation) are studied from the process thresholds up to 100 - 300 eV. It is found unambiguously that the resonance excitation of ion contributes substan-tially ( 30 - 50 %) into the excitation cross section not only in the near-threshold incident electron energy region, where it is due mainly to the autoionizing states decaying via the Coster-Kronig process, but also in the entire energy region under study being resulted from the decay of the autoionizing states formed predomi-nantly at the subvalence d10 shell excitation or at the simultaneous excitation of both the subvalence and valence s (or s2) shells. It is shown that the effective ( 10-16 cm2) cross section of both the dielectronic and trielectronic recombination results from the effect of correlation interaction in the many-electron atomic sys-tems leading to essential increase of the probability of the radiative decay of autoionizing states. It is found that the absolute values of the electron-impact s- and d-ionization of the In+ ion reach nearly the 10-17 cm2 value testifying to the high efficiency of ionization with simultaneous ion excitation. This results from a con-siderable contribution of the indirect ionization process (i.e. excitation-ionization) to the direct ionization with excitation. An important role of correlation effects re-lated to the d and s-electron competition in the excitation, ionization and recombi-nation processes in many-electron ions is found showing that the influence of the subvalence d10 shell increases with that of the atomic number.