| Автор | Keith Berrington |
| Автор | John Pelan |
| Автор | Lisa Quigley |
| Дата выпуска | 1997-11-14 |
| dc.description | We present new R-matrix calculations for ionization processes involving the beryllium K-shell, namely electron impact ionization of and single and double photoionization of Be. These are modelled near inner-shell thresholds in a unified way, coupling direct and indirect processes, enabling comparison of the respective autoionization features. Below the K edge, we predict that direct double photoionization contributes 4% to the total cross section background for photoionizing Be; the onset of K-shell excitation - autoionization (EA), an indirect mechanism, increases the background by a factor 20. By contrast, we find that EA in ionization increases its background by only 4%; this is less than previous estimates, but in line with experiment. We also study high-energy behaviour for photoionizing excited states, e.g. , where we find a background dominated by ionization. This process is normally omitted in R-matrix schemes used in opacity and recombination calculations, leading to orders-of-magnitude underestimation at high energies of excited-state photoionization, which also exhibits a large core resonance above the K edge. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Electron impact ionization of and photoionization of Be at the K edge |
| Тип | paper |
| DOI | 10.1088/0953-4075/30/21/030 |
| Electronic ISSN | 1361-6455 |
| Print ISSN | 0953-4075 |
| Журнал | Journal of Physics B: Atomic, Molecular and Optical Physics |
| Том | 30 |
| Первая страница | 4973 |
| Последняя страница | 4990 |
| Аффилиация | Keith Berrington; Department of Applied Mathematics and Theoretical Physics, Queen's University, Belfast BT7 1NN, UK |
| Аффилиация | John Pelan; Department of Applied Mathematics and Theoretical Physics, Queen's University, Belfast BT7 1NN, UK |
| Аффилиация | Lisa Quigley; Department of Applied Mathematics and Theoretical Physics, Queen's University, Belfast BT7 1NN, UK |
| Выпуск | 21 |
