| 1. |
- Fei, Z., et al.
(författare)
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Experimental and theoretical study of the ground-state M1 transition in Ag-like tungsten
- 2012
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 86:6
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Tidskriftsartikel (refereegranskat)abstract
- We present an experimental and theoretical study of the F-2(5/2) -> F-2(7/2) M1 transition in Ag-like W (W27+). The experiments employed the Shanghai permanent magnet electron beam ion trap, which has been developed especially for assisting spectroscopic diagnostics of edge plasmas for magnetic fusion devices. The theoretical value was obtained using the GRASP2K set of computer codes and included a comprehensive correlation study. The experimental M1 wavelength was measured as 3377.43 +/- 0.26 angstrom (3378.43 angstrom vacuum wavelength), whereas the calculated wavelength is in good agreement at 3381.80 angstrom. This good agreement shows the importance of fully understanding the electron correlation effects to predict the energy of the fine structure even in this, for tungsten, relatively simple case.
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| 2. |
- Hartman, Henrik, et al.
(författare)
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Negative ion relaxation and reactions in a cryogenic storage ring
- 2020
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Ingår i: Journal of Physics: Conference Series Vol 1412. - : IOP Publishing. - 1742-6588 .- 1742-6596.
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Konferensbidrag (refereegranskat)abstract
- An overview of recent experimental results of studies of negative atomic and molecular ions in the Double ElectroStatic Ion-Ring ExpEriment, DESIREE is given. Metastable level lifetimes in atomic negative ions have been measured by time-dependent laser photodetachment. Rotational relaxation of diatomic anions is studied by near-threshold photodetachment. Spontaneous decays of small metal cluster anions by electron emission and fragmentation is studied with decay-channel specificity. Finally, mutual neutralisation of pairs of negative and positive ions has been investigated with initial and final state selectivity.
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| 3. |
- Kristiansson, Moa K., et al.
(författare)
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Experimental and theoretical studies of excited states in Ir
- 2021
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Ingår i: Physical Review A. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 103:6
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Tidskriftsartikel (refereegranskat)abstract
- The properties of atomic negative ions are to a large extent determined by electron-electron correlation which makes them an ideal testing ground for atomic many-body physics. In this paper, we present a detailed experimental and theoretical study of excited states in the negative ion of iridium. The ions were stored at cryogenic temperatures using the double electrostatic ion ring experiment facility at Stockholm University. Laser photodetachment was used to monitor the relaxation of three bound excited states belonging to the [Xe] 4f(14)5d(8)6s(2) ionic ground configuration. Our measurements show that the first excited state has a lifetime much longer than the ion-beam storage time of 1230 +/- 100 s. The binding energy of this state was measured to be 1.045 +/- 0.002 eV. The lifetimes of the second and third excited states were experimentally determined to be 133 +/- 10 and 172 +/- 35 ms, respectively. Multiconfiguration Dirac-Hartree-Fock calculations were performed in order to extract binding energies and lifetimes. These calculations predict the existence of the third excited bound state that was detected experimentally. The computed lifetimes for the three excited bound states agree well with the experimental results and allow for a clear identification of the detected levels.
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| 4. |
- Zhao, R., et al.
(författare)
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The M1 ground state fine structure transition in Ag-like Yb
- 2014
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 47:18
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Tidskriftsartikel (refereegranskat)abstract
- In our previous work, the agreement between the theoretical and measured wavelength for the 4f-M1 transition of Ag-like W shed light on the importance of a careful treatment of all core-valence correlation effects to obtain a reliable value of this fine structure energy separation. To confirm these results and extend the analysis isoelectronically, we have undertaken an experimental and theoretical study of the same M1 transition in Ag-like Yb. The measured wavelength for this M1 transition is 515.77 +/- 0.10 nm (515.91 nm in vacuum) which agrees well with our ab initio theoretical value of 515.48 nm.
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