Journalartikel

Jahr der Veröffentlichung: 2005

Zeitschrift: Physical review A

Bandnummer: 72

Heftnummer: 3

ISSN: 1050-2947

eISSN: 1094-1622

DOI Link: https://doi.org/10.1103/PhysRevA.72.032713

Verlag: American Physical Society

Abstract: 
Theoretical calculations and experimental crossed-beam measurements are compared for electron-impact single ionization of Pbq+ ions for q=1-10. We compare with two main theoretical methods. First, we check against configuration-average distorted-wave calculations, which include both direct-ionization and indirect excitation-autoionization contributions. Second, for ion stages Pb+ through to Pb5+, we calculate the dominant excitation-autoionization channels using level-resolved distorted-wave theory to evaluate the excitation cross sections. We find that for ion stages Pb+, Pb2+, and Pb3+, distorted-wave theory significantly overestimates the total-ionization cross section, due to an overestimation of the direct-ionization cross section from the 5d subshell. For ion stages Pb4+ through to Pb10+ there is good agreement between theory and experiment. We find evidence for significant metastable fraction in the ion beam of the experiment for ion stages Pb2+, Pb3+, Pb4+, Pb5+, and Pb6+. For ion stage Pb3+ we find that the level-resolved distorted-wave calculation of the excitation autoionization results in a slight reduction of the configuration-average theoretical results, due to splitting of levels within the autoionizing configurations. We also investigate two semiempirical methods of calculating the direct-ionization cross sections: namely, the Lotz method and the binary encounter Bethe method. We find that both methods provide results which are significantly lower than the distorted-wave method for the 5d-subshell direct ionization of Pb+, Pb2+, and Pb3+. For the higher ion stages, both methods are lower than the distorted-wave direct-ionization cross-section results, trending towards the distorted-wave results as the ion stage increases.

Harvard-Zitierstil: Loch, S., Ludlow, J., Pindzola, M., Scheuermann, F., Kramer, K., Fabian, B., et al. (2005) Electron-impact ionization of Pb^q+ ions for q=1-10 -: art. no. 032713, PHYSICAL REVIEW A, 72(3), Article 032713. https://doi.org/10.1103/PhysRevA.72.032713

APA-Zitierstil: Loch, S., Ludlow, J., Pindzola, M., Scheuermann, F., Kramer, K., Fabian, B., Huber, K., & Salzborn, E. (2005). Electron-impact ionization of Pb^q+ ions for q=1-10 -: art. no. 032713. PHYSICAL REVIEW A. 72(3), Article 032713. https://doi.org/10.1103/PhysRevA.72.032713