Electron-impact double ionization of magnesium

Abstract

Theory and experiment are compared for the electron-impact double ionization of Mg. Direct ionization cross sections, involving the simultaneous ionization of both 3s electrons, are calculated using a non-perturbative time-dependent close-coupling method. Indirect ionization cross sections, involving the ionization of either a 2p or 2s electron followed by autoionization, are calculated using a perturbative time-independent distorted-wave method. At low energies the direct ionization cross sections are found to be in good agreement with experiments, while at the higher energies the indirect ionization cross sections are also found to be in good agreement with experiments.

Single and double ionization of magnesium by electron impact: A classical study

“…For example, time-dependent close coupling (TDCC) [19], R-matrix with pseudostates (RMPSs) [20], and convergent close coupling (CCC) [21], are tested and benchmarked (see, e.g., Refs. [18,22,23]). Cross sections for Mg have been measured experimentally since the 70s and analyzed theoretically ever since (see Refs.…”

Evidence for unnatural-parity contributions to electron-impact ionization of laser-aligned atoms

“…We note that a calculation at a fixed angle value of 35 • (not shown) is reasonably close to the measured cross section, but this is outside the measurement uncertainty of ±5 • in the fixed angle value. Figure 5 Finally, we note that a three-electron TDCC method can also be applied to the computation of the single ionization of Mg or Ca, in a similar manner to the calculations used for the electron-impact double ionization of Mg that were recently reported [30]. Such threeelectron calculations have an advantage compared to two-electron calculations in that one can construct the initial state to be the 3s3p 1 P term, which of course is the real initial state of the measurements with which we compare here.…”

Electron-impact double ionization of B+

“…In keeping with previous calculations for He, Be and Mg, we used a (192) 3 point lattice with a uniform mesh spacing of r = 0.20 to propagate the TDCC(3e) equations in real time for L = 0 − 5 S = 1 2 total symmetries and for incident energies of 100 eV, 150 eV and 200 eV. As used in previous TDCC(3e) calculations for Be [3] and Mg [4], the number of coupled channels, (l 1 l 2 Ll 3 ), ranged from 11 for L = 0 to 81 for L = 5, while the partial cross sections were extrapolated to higher L using a nonlinear angular momentum fitting expression given by…”