| 1. |
- Biemont, E., et al.
(författare)
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Lifetime measurements and calculations in Y+ and Y2+ ions
- 2011
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 1365-2966 .- 0035-8711. ; 414:4, s. 3350-3359
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Tidskriftsartikel (refereegranskat)abstract
- We report a new set oftheoretical transition probabilities in Y II, obtained using a multiconfiguration relativistic Hartree-Fock method including core polarization. The overall quality of the calculations is assessed by comparisons with new and previous lifetime measurements. In this paper, we report new measurements of five lifetimes in the 4d5p and 5s5p configurations, in the energy range of 32 048-44 569 cm(-1), obtained by the time-resolved laser-induced fluorescence method. A similar theoretical model, applied to Y III, leads to results in good agreement with new laser measurements of two 5p levels obtained in this work and with previous beam-foil results for 5d and 6s levels. An extensive set of oscillator strengths is also proposed for Y III.
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| 2. |
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| 3. |
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| 4. |
- Hartman, Henrik, et al.
(författare)
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Experimental and theoretical lifetimes and transition probabilities in Sb i
- 2010
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physiological Society. - 1050-2947 .- 1094-1622. ; 82:5
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Tidskriftsartikel (refereegranskat)abstract
- We present experimental atomic lifetimes for 12 levels in Sb i. The levels belong to the 5p2(3P)6s 2P, 4P, and 5p2(3P)5d 4P, 4F, and 2F terms. The lifetimes were measured using time-resolved laser-induced fluorescence. In addition, we report calculations of transition probabilities in Sb i using a multiconfigurational Dirac-Hartree-Fock method. The physical model was tested through comparisons between theoretical and experimental lifetimes for 5d and 6s levels. The lifetimes of the 5d 4F3/2,5/2,7/2 levels (19.5, 7.8, and 54 ns, respectively) depend strongly on the J value. This is explained by different degrees of level mixing for the different levels in the 4F term.
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| 5. |
- Hartman, Henrik, et al.
(författare)
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Radiative data for highly excited 3d84d levels in Ni II from laboratory measurements and atomic calculations
- 2017
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 600
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Tidskriftsartikel (refereegranskat)abstract
- Aims: This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions from 3d84d levels of astrophysical interest in singly ionized nickel. Methods: Radiative lifetimes of seven high-lying levels of even parity in Ni II (98 400-100 600 cm-1) have been measured using the time-resolved laser-induced fluorescence method. Two-step photon excitation of ions produced by laser ablation has been utilized to populate the levels. Theoretical calculations of the radiative lifetimes of the measured levels and transition probabilities from these levels are reported. The calculations have been performed using a pseudo-relativistic Hartree-Fock method, taking into account core polarization effects. Results: A new set of transition probabilities and oscillator strengths has been deduced for 477 Ni II transitions of astrophysical interest in the spectral range 194-520 nm depopulating even parity 3d84d levels. The new calculated gf-values are, on the average, about 20% higher than a previous calculation and yield lifetimes within 5% of the experimental values.
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| 6. |
- Holmes, Charlotte, et al.
(författare)
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Experimentally Measured Radiative Lifetimes and Oscillator Strengths in Neutral Vanadium
- 2016
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Ingår i: Astrophysical Journal Supplement Series. - : Bibliopolis, Edizioni di Filosofia e Scienze. - 0067-0049 .- 1538-4365. ; 224:2
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Tidskriftsartikel (refereegranskat)abstract
- We report a new study of the V i atom using a combination of time-resolved laser-induced fluorescence and Fourier transform spectroscopy that contains newly measured radiative lifetimes for 25 levels between 24,648 cm-1 and 37,518 cm-1 and oscillator strengths for 208 lines between 3040 and 20000 Å from 39 upper energy levels. Thirteen of these oscillator strengths have not been reported previously. This work was conducted independently of the recent studies of neutral vanadium lifetimes and oscillator strengths carried out by Den Hartog et al. and Lawler et al., and thus serves as a means to verify those measurements. Where our data overlap with their data, we generally find extremely good agreement in both level lifetimes and oscillator strengths. However, we also find evidence that Lawler et al. have systematically underestimated oscillator strengths for lines in the region of 9000 ± 100 Å. We suggest a correction of 0.18 ± 0.03 dex for these values to bring them into agreement with our results and those of Whaling et al. We also report new measurements of hyperfine structure splitting factors for three odd levels of V i lying between 24,700 and 28,400 cm-1.
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| 7. |
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| 8. |
- Macheva, G, et al.
(författare)
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Radiative lifetimes and transition probabilities in Rh I
- 2015
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 450:1, s. 223-228
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes of 17 high-lying excited states in Rh I aremeasured using the time-resolved laser-induced fluorescence method. Out of these lifetimes, 13 are new and the remaining four confirm previous measurements. Furthermore, we report the first theoretical investigation of Rh I, where the radiative decay properties of all experimentally known levels below 47 000 cm−1 are calculated using a pseudo-relativistic Hartree–Fock method including core polarization effects. The theoretical calculations are found to be in very good agreement with the experimental results. A large set of new transition probabilities is presented for lines of astrophysical interest in the spectral range 2200–10 000 Å.
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| 9. |
- Malcheva, G., et al.
(författare)
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Lifetime measurements of even and odd states in neutral terbium (Tb I)
- 2013
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 88:4
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes of 7 odd and 11 even parity states of Tb I (Z = 65) have been measured by the time resolved laser induced fluorescence method (TR-LIF). Experimental data for 9 out of the 18 states are obtained for the first time. The radiative lifetimes presented in this study are in good agreement with previous TR-LIF experimental results but systematically shorter than those obtained by the delayed coincidence technique.
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