| Autor: |
M.W. Lucas, M. Kuzel, K. O. Groeneveld, D. H. Jakubaßa-Amundsen |
| Rok vydání: |
1997 |
| Předmět: |
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| Zdroj: |
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 124:263-270 |
| ISSN: |
0168-583X |
| DOI: |
10.1016/s0168-583x(96)01060-9 |
| Popis: |
We summarize systematic studies of projectile ionisation in strongly asymmetric collisions. The simplest electron carrying projectiles, H 0 and the H 2 + molecule at intermediate energies (0.5 MeV/u), impinge on the heavy atoms Ar, Kr and Xe. The electrons ejected in these collisions are recorded in the complete angular range 0° ≤ θ ≤ 180°. The singly differential cross sections show pronounced minima due to the quantal generalised Ramsauer-Townsend (RT) effect and are very similar to those for the elastic scattering of free electrons. Closer analysis of the electrons lost by the projectile reveals that the RT effect affects not only their intensity but also their position and width. In the angular range around the minima, the loss peak is shifted to lower energy by as much as 40 eV and broadened considerably. In the calculated doubly differential spectra one identifies a peak splitting with a rising low energy component to be responsible for this phenomenon. The electron impact approximation — in the framework of a quasifree electron scattering by the target potential — shows good agreement with the experiments. Therefore, in these strongly asymmetric collisions, the loosely bound projectile electrons can be understood as quasifree. The calculated DI processes have a limited accuracy and tend to overestimate the influence of the RT effect on the loss peak. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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