Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 10: Posters Wednesday (Cooling and Trapping, Electron Scattering and Recombination)
A 10.31: Poster
Mittwoch, 4. April 2001, 12:30–15:00, AT3
Doorway-state calculation of low-energy electron recombination with Au25+ — •Gleb Gribakin1, Anna Gribakina2, Victor Flambaum2, and Celal Harabati2 — 1Department of Applied Mathematics and Theoretical Physics, Queen’s University, Belfast BT7 1NN, UK — 2School of Physics, University of New South Wales, Sydney 2052, Australia
Low-energy electron recombination with the Au25+ ion is dominated by resonances. They have not been seen experimentally because of the very high energy density, but their energy-averaged contribution to the recombination rate exceeds that of the direct radiative recombination by a factor of 150. As we showed earlier [Aust. J. Phys. 52, 443 (1999)], these resonances are chaotic multiply-excited states containing N ∼ 30000 basic components with almost random coefficients. For a given Jπ they have a mean level spacing D∼ 1 meV near the ionization threshold. Now we have estimated the radiative width Γ r and the ratio Γ a/D, where Γ a is the autoionisation width. The latter is suppressed by a factor of N compared to that of simple dielectronic resonances. On the other hand, Γ r∼ D. As a result, Γ r≫ Γ a, and the fluorescence yield of the resonances is close to unity. Our calculation explains the experimentally observed enhancement of the recombination rate.