| 1. |
- Biémont, E, et al.
(författare)
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Decay of metastable states in Nd II
- 2007
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Ingår i: The European physical journal D Atomic, molecular and optical physics. ; 41, s. 211-
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Carlsson, Ella, et al.
(författare)
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Mass composition of the escaping plasma at Mars
- 2006
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Ingår i: Icarus. - : Elsevier BV. - 0019-1035 .- 1090-2643. ; 182:2, s. 320-328
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Tidskriftsartikel (refereegranskat)abstract
- Data from the Ion Mass Analyzer (IMA) sensor of the ASPERA-3 instrument suite on Mars Express have been analyzed to determine the mass composition of the escaping ion species at Mars. We have examined 77 different ion-beam events and we present the results in terms of flux ratios between the following ion species: CO2+/O+ and O-2(+)/O+. The following ratios averaged over all events and energies were identified: CO2+/O+ = 0.2 and O-2(+)/O+ = 0.9. The values measured are significantly higher, by a factor of 10 for O-2(+)/O+, than a contemporary modeled ratio for the maximum fluxes which the martian ionosphere can supply. The most abundant ion species was found to be O+, followed by O-2(+) and CO2+. We estimate the loss of CO2+ to be 4.0 x 10(24) s(-1) (0.29 kg s(-1)) by using the previous measurements of Phobos-2 in our calculations. The dependence of the ion ratios in relation to their energy ranges we studied, 0.3-3.0 keV, indicated that no clear correlation was found.
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| 3. |
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| 4. |
- Gisselbrecht, Mathieu, et al.
(författare)
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Photon energy dependence of fragmentation of small argon clusters
- 2005
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 123:19
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Tidskriftsartikel (refereegranskat)abstract
- Photofragmentation of small argon clusters with size below ten atoms is reported. In this size range significant modifications from the electronic properties and geometry take place. When tuning the photon energy through the argon 2p edge, the fragmentation pattern is changed. Specifically, cation dimer production is enhanced at the 2p(3/2)-> 4s resonance, while above the 2p edge almost complete atomization is observed. In both cases, the widths of the peaks in the mass spectra indicate that a large amount of kinetic energy is imparted to the fragment due to the formation of multiply charged clusters. A model based on "Coulomb explosion"-charge separation, simply resulting in a complete atomization of the cluster with no dependence on the photon energy-is insufficient to explain the observed photofragmentation of small clusters.
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| 5. |
- Golubev, Pavel, et al.
(författare)
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Pion Emission in H-2,C-12,Al-27(gamma,pi+) Reactions at Threshold
- 2008
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Ingår i: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 806:1-4, s. 216-229
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Tidskriftsartikel (refereegranskat)abstract
- The very first data from MAX-lab in Lund, Sweden on pion photoproduction at threshold energies are presented. The decrease of the total π+ yield in γ+12C, 27Al reactions below 200 MeV as well as the dσ/dΩ cross-section data essentially follow the predictions of an intranuclear-cascade model with an attractive potential for the pion–nucleus interaction. However, View the MathML source, cross-section data at 176 MeV show deviations which call for refinements of the model and possibly also for the inclusion of coherent pion-production mechanisms.
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| 6. |
- Gurell, Jonas, 1981-, et al.
(författare)
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Laser-probing measurements and calculations of lifetimes of the 5d 2D3/2 and 5d 2D5/2 metastable levels in Ba II
- 2007
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 75:5, s. 052506-
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Tidskriftsartikel (refereegranskat)abstract
- The two metastable levels 5d 2D3∕2 and 5d 2D5∕2 in Ba II both show extremely long lifetimes of the order of several tens of seconds each. This has been found both by experiments and by theoretical predictions. The small transition probabilities associated with these two levels make them interesting and challenging for theoreticians as well as for experimentalists. Several calculations and measurements of these two lifetimes have been made previously but discrepancies between the results are present. This article presents values of τ=89.4±15.6 s for the 2D3∕2 level and τ=32.0±4.6 s for the 2D5∕2 level measured in a beam-laser experiment performed at the ion storage ring CRYRING. These values are supported by our new calculations resulting in τ=82.0 s for the 2D3∕2 level and τ=31.6 s for the 2D5∕2 level.
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