Merged-beams energy-loss technique for electron-ion excitation: Absolute total cross sections forO5+(2s→2p)
| Autor: | Mark E. Bannister, E W. Bell, J. L. Forand, K. Rinn, X. Q. Guo, J. S. Thompson, Alan Smith, Brett DePaola, Gordon H. Dunn, E. K. Wåhlin, Alfred Müller, D. S. Belić, David Richard Swenson, D. C. Gregory, C. A. Timmer, R. A. Phaneuf |
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| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | Physical Review A. 49:4585-4596 |
| ISSN: | 1094-1622 1050-2947 |
| DOI: | 10.1103/physreva.49.4585 |
| Popis: | A merged-beams electron-energy-loss technique is described, by which absolute cross sections can be measured for near-threshold electron-impact excitation of multipy charged ions. Results are reported here for absolute total electron-impact excitation cross sections for the ${\mathrm{O}}^{5+}$(2s\ensuremath{\rightarrow}2p) transition from below threshold to 1.6 eV above threshold. The experimental data are in good agremeent with a seven-state close-coupling calculation throughout the energy range of the experiment. Results agree with calculations showing that more than 90% of the electrons causing excitation are ejected in the backward direction in the center-of-mass frame. This backscattering is shown in both quantum-mechanical and semiclassical calculations. Evidence is observed for high-lying metastable autoionizing states with a lifetime of approximately 0.9 \ensuremath{\mu}s which are made to ionize by electron impact. |
| Databáze: | OpenAIRE |
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