State-selective electron capture by 18-keV Kr{sup 8+} ions from laser-excited Rb{sup {asterisk}}(15{ital p}{endash}25{ital p}) Rydberg atoms
- Service des Photons, Atomes et Molecules, DRECAM, CEA/Saclay, 91191 Gif-sur-Yvette-Cedex (France)
State-selective single electron capture, in collisions of multicharged ions Kr{sup 8+} at 18 keV with laser-excited Rydberg Rb{sup {asterisk}}({ital n}{sub {ital ip}}) atoms, is investigated by use of a field ionizing lens system (FILS), in a three-crossed-beam experiment. By scanning the laser over a wide range of wavelengths (303{endash}298 nm), this investigation covers the 15{ital p}{endash}25{ital p} Rydberg series, showing the influence of the initial state of Rb. For every well-defined Rb{sup {asterisk}}({ital n}{sub {ital ip}}) state, (i) very high Rydberg states of the Kr{sup 7+{asterisk}}({ital n}) product ions are detected as a consequence of the high degree of excitation of the target and of the high charge of the projectile, and (ii) the {ital n} distribution of the capture cross section is obtained in the domain 67{le}{ital n}{le}95, by measuring the energy spectrum of the Kr{sup 8+} ions produced by field ionization in the FILS of the excited product ions Kr{sup 7+{asterisk}}. These {ital n} distributions become wider and are systematically shifted towards higher {ital n} values as {ital n}{sub {ital i}} increases. By using the classical trajectory Monte Carlo method, the {ital n} distributions are calculated for the {ital n}{sub {ital ip}} series. Although the calculated {ital n} distributions are systematically wider, the behavior of their widths and of their relative positions is in agreement with the experiment. On the other hand, the extended classical over-the-barrier model yields {ital n} distributions significantly narrower than the experimental ones. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 388277
- Journal Information:
- Physical Review A, Journal Name: Physical Review A Journal Issue: 5 Vol. 54; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
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