Electron-impact single ionization of Kr¹⁰⁺and Kr¹¹⁺ions

Abstract

Cross sections for electron-impact single ionization of ground state Kr 10+ and Kr 11+ ions have been calculated in the distorted-wave approximation including both direct ionization and excitation-autoionization processes. The direct ionization cross sections are calculated for the ejection of 3s, 3p and 3d subshell electrons and the excitation-autoionization cross sections are calculated for the inner-shell excitations of the type 3p → nl (n = 4, 5, 6; l = 0, 1, 2, 3) and 3s → n l (n = 4, 5; l = 0, 1, 2, 3). In addition, the inner-shell excitation of the type 2p → 3d, 4l (l = 0, 1, 2, 3) is included for Kr 11+ . The radiative decay effect has been found to be negligible by carrying out explicit calculations of the radiative rates and autoionizing rates. The present results show that the direct process dominates the total ionization cross section for the two ions and that the contributions of excitation-autoionization are about 15% and 13% of the total cross sections for Kr 10+ and Kr 11+ ions, respectively. The present results are in good agreement with the experimental measurement of Oualim et al.

Electron-impact single ionization of krypton ions (q= 12-18)

“…For the metastable configuration, the Lotz semi-empirical formula for direct ionization of the 3s, 3p and 3d subshells is shown together with the results of a ACDW calculation. The same theoretical method was applied previously for Kr 10+ and Kr 11+ (Teng et al 2000). The detailed description and discussion of the calculation will be published later.…”

“…Experimental cross sections for Kr q+ (q = 1-11) have been published: for example, for charge states 1 (Man et al 1987, Tinschert et al 1987, 2 (Man et al 1993, Tinschert et al 1987, Gregory 1985, 3 (Gregory et al 1983, Tinschert et al 1987, 4, 5 and 7 (Bannister et al 1994), 8 (Bannister et al 1988), 9 (Gregory and Bannister 1994) and 10 and 11 (Oualim et al 1995). Theoretical cross sections have been obtained for charge states 4-7 (Gorczyca et al 1994a), 10-11 (Teng et al 2000) and 18 (Younger 1982). Energy thresholds corresponding to ionization and excitation of outer-or inner-shell electron are estimated from the Hartree-Fock structure calculation of Blanke et al (1992).…”

Electron impact ionization of Kr XI–Kr XIX ions

“…The levels 1s 2 2s2p 6 3s 2 3p 6 3d m nl and 1s 2 2s 2 2p 5 3s 2 3p 6 3d m nl (quantum numbers nl include 3d) after autoionization give the singly ionized ion. The radiative decay probability is much smaller than the autoionization one in this case (see also Teng et al 2000). Thus 1 for Kr XIII from the 3s 2 3p 6 3d 6 state; but the dash-dotted curves here represent the calculations of Loch et al (2002): total cross sections (upper curve) and direct ionization from the 3s, 3p, 3d shells only (lower curve).…”

“…Ionization cross sections of Kr XI from the 3s 2 3p 6 3d 8 state; '×', experimental data; solid curve, calculated total ionization cross section; the lower dashed curve represents direct ionization from the 3s, 3p, 3d shells only and, for the upper dashed curve, excitation from the 2s, 2p inner shells is added to the previous one; the calculations of Teng et al (2000) are represented by dashdotted curves: total cross sections (upper curve) and direct ionization from the 3s, 3p, 3d shells only (lower curve).…”

Updating of atomic data needed for ionization balance evaluations of krypton and molybdenum

“…Experimental data on ionisation cross sections σ as a function of the impacting-electron energy E are available for the Kr ions from neutral Kr I up to Ar-like Kr XIX, with the single exception of Zn-like Kr VII. These data are given in Refs [28][29][30][31][32][33][34][35][36][37][38] and are individually treated in the following discussion. Supplementary unpublished σ (Ε) data by D. Gregory for Kr VIII and Kr X and by R. Howald for Kr V can be found on the Oak Ridge National Laboratory (ORNL) web site [39].…”