On resonance processes in near-threshold excitation of the resonance lines of a Zn+ ion in electron-ion collisions

The excitation of the components of the 4p(2)P(1/2,3/2)(0) resonance doublet of the Zn+ ion by monoenergetic electrons in the interval 4-10 eV is investigated by a spectroscopic method in crossed beams. Resonances are found in the energy dependences below and above the excitation thresholds of resonance lines. The subthreshold resonances are satellite of the lines investigated and are excited in the process of dielectronic recombination. The main competing process here is the electronic decay of autoionizing states, which is manifested in a resonance excitation of the ions starting at the thresholds for the excitation of the levels. Autoionizing states lying between the levels of the doublet splitting of the 4p(2)P(1/2,3/2)(0) state decay to the 4p(2)P(1/2)(0) level in a Koster-Kronig process. Above the excitation energy of the 4p(2)P(3/2)(0) level the the dominant contribution to resonance excitation is from autoionizing states with configurations 3d(9)(D-2(5/2,3/2))4s(2)np,(n - 1) f. (C) 1998 American Institute of Physics. [S0021-3640(98)00420-4].