| 1. |
- Tokman, M, et al.
(författare)
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Dielectronic recombination resonances in F6
- 2002
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 1050-2947. ; 66:1, s. 012703/1-012703/13
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Tidskriftsartikel (refereegranskat)abstract
- Electron-ion recombination spectra of the Li-like ion F6+ in the energy range 0.0-0.6 eV from two different ion storage rings are presented, showing excellent agreement. The experimental results are compared with a calculated spectrum, obtained by combination of relativistic many-body methods and complex rotation, and the agreement is found to be very good. The recombination spectrum in the studied energy region is determined by the 2p6l dielectronic recombination resonances. The lowest-energy resonances are found around 10 meV, and include one broad resonance overlapping the threshold. The recombination rate coefficients are, even in this region, very well accounted for by the calculation. It is further shown that the nonrelativistically allowed resonances contribute to less than 60% of the integrated rate coefficients in the specified energy range.
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| 2. |
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| 3. |
- Böhm, S, et al.
(författare)
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Enhancement of dielectronic recombination by external electromagnetic fields
- 2003
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Ingår i: Hyperfine Interactions. - 0304-3843. ; 146-147:1-4, s. 23-27
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Tidskriftsartikel (refereegranskat)abstract
- The enhancement of the dielectronic recombination rate of lithiumlike Ne7+ and O5+ ions by external electromagnetic fields has been measured at the storage ring CRYRING. The energy range covered all 1s(2)2pnl dielectronic recombination resonances attached to the 2s --> 2p core excitation. Electric fields up to 1436 V/cm were applied in the Ne7+ experiment and the saturation of the enhancement with increasing electric field could clearly be seen. In the O5+ experiment the enhancement was studied as a function of the Rydberg quantum number n.
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| 4. |
- Böhm, S, et al.
(författare)
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Influence of electromagnetic fields on the dielectronic recombination of Ne7+ and O5+ ions
- 2001
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Ingår i: Physica Scripta. Topical Issues. - 0281-1847. ; T92, s. 395-397
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Tidskriftsartikel (refereegranskat)abstract
- Within a series of measurements of the dielectronic recombination (DR) of lithium-like ions we have determined the enhancement of the recombination rate in the presence of crossed electric and magnetic fields for Ne7+ and O5+ ions. In both cases the electron energy range covers a DR resonances attached to 2s --> 2p(1/2) and 2s --> 2p(3/2) Delta_n = 0 core excitations. For increasing field the enhancement factor first increases linearly with the electric field and then saturates. In order to investigate the field effect on high-n Rydberg states the ion energy in the O5+ experiment was changed from 9.4 MeV/u to 5 MeV/u and 3.26 MeV/u. With the variation of the ion energy the field ionization of Rydberg states in the analyzing magnet is influenced. This enabled us to study the field enhancement for a narrow bandwidth of n-states.
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| 5. |
- Böhm, S, et al.
(författare)
-
Influence of electromagnetic fields on the dielectronic recombination of Ne7+ ions
- 2001
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947. ; 64:3, s. 032707/1-032707/7
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Tidskriftsartikel (refereegranskat)abstract
- The influence of crossed electric and magnetic fields on dielectronic recombination of Ne7+ ions has been measured at the Stockholm heavy-ion storage ring CRYRING. The electron energy range covered all dielectronic recombination resonances attached to 2s-2p1/2 and 2s-2p3/2 core excitations. Two sets of measurements at magnetic fields of 180 mT and 30 mT have been performed. For the measurement at 180 mT we applied 25 different electric fields between 0 and 1400 V/cm. The resonance strength for dielectronic recombination via high Rydberg states initially increases linearly with electric field and later levels out. At a magnetic field of 30 mT we applied 15 different electric fields ranging from 0 to 140 V/cm. Compared to the measurement at 180 mT the initial slope of the rate enhancement was larger by almost a factor of 2. The fraction of resonant strength not measured due to field ionization is estimated by a model calculation of dielectronic recombination cross sections.
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| 6. |
- Tokman, M, et al.
(författare)
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Towards a determination of QED effects in Cu-like Pb recombination resonances near threshold
- 2001
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Ingår i: Physica Scripta. Topical Issues. - 0281-1847. ; T92, s. 406-409
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Tidskriftsartikel (refereegranskat)abstract
- Dielectronic recombination of Pb53+ has been studied and a resonance is detected only similar to 10(-4) eV above the ground state. The possibility to determine the Pb53+ (4p(1/2)) - Ph53+ (4s(1/2)) energy splitting with a similar accuracy from the determination of the resonance position is discussed. Such a precision can only be achieved by calculations which treat quantum electrodynamics (QED) in a many-body environment at a level which can still not be reached. A fully relativistic many-body calculation of the splitting is described and the uncertainties are discussed.
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