Overview over the present single-ionization cross sections of Sn4 + through Sn13 + ions

Figure 1. Overview over the present single-ionization cross sections of Sn4 + through Sn13 + ions. The cross-section scale is in units of 10−17 cm2 and the cross section for each next ion stage is shifted downwards by 1 × 10−17 cm2 and multiplied by a certain coefficient provided on the graph. The thin kinked polygon connects the ground-state ionization thresholds marked by short vertical bars.

Abstract

Electron-impact single-ionization cross sections of Snq + ions in charge states q = 4–13 with 4d[10 − (q − 4)] outer-shell configurations have been studied in the energy range from the corresponding thresholds up to 1000 eV. Absolute cross sections and fine-step energy-scan data have been measured employing the crossed-beams technique. Contributions of different ionization mechanisms have been analysed by comparing the experimental data with calculations employing the configuration-averaged distorted wave approximation. Ionization plasma rate coefficients inferred from the experimental data are also presented.