| 1. |
- Bengtsson, G. J, et al.
(författare)
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Determination of Radiative Lifetimes In Neutral Arsenic Using Time-resolved Laser Spectroscopy In the Vuv Region
- 1992
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Ingår i: Astronomy & Astrophysics. - 0004-6361. ; 263:1-2, s. 440-442
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Tidskriftsartikel (refereegranskat)abstract
- Inspired by the recent Hubble Space Telescope first observations of arsenic in an astrophysical object we have determined the natural radiative lifetime of the upper states of two of the three resonance lines of As I. Short pulse laser excitation at 193.7 and 197.2 nm was achieved using different non-linear optical mixing schemes. Using time-resolved spectroscopy we obtain tau(4p(2)5s P-4(3/2))=4.3(5) ns and T(4p(2)5s P-4(1/2)=4.5(5)ns yielding the absorption oscillator strengths f(abs)(193.7 nm) =0.123 (17) and f(abs)(1 97.2 nm)=0.059(8).
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| 2. |
- Bengtsson, G. J, et al.
(författare)
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Oscillator-strengths For Resonance Transitions In Neutral Selenium and Tellurium Derived From Time-resolved Laser Spectroscopy
- 1992
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Ingår i: Zeitschrift für Physik D Atoms, Molecules and Clusters. - 0178-7683. ; 23:1, s. 29-32
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Tidskriftsartikel (refereegranskat)abstract
- We have measured radiative lifetimes for selenium and tellurium resonance levels by using short pulse laser excitation in differentially heated resonance cells. We obtained tau(3S1 Se I) = 2.9(5) ns and tau(3S1 Te I) = 3.1(5) ns, which together with branching ratio values given by Ubelis and Berzinsh yield the absorption oscillator strength f(abs)(Se I, 196.0 nm) = 0.074(16) and f(abs)(Te I, 214.3 nm) = 0.098(17).
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| 3. |
- Bengtsson, G. J, et al.
(författare)
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Radiative-lifetime and Lande-factor Measurements of the Se-i 4p(3)5s (5)s(2) Level Using Pulsed Laser Spectroscopy
- 1992
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Ingår i: Journal de Physique II. - : EDP Sciences. - 1155-4312 .- 1286-4870. ; 2:4, s. 773-779
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Tidskriftsartikel (refereegranskat)abstract
- First laser spectroscopic investigations on atomic selenium are reported. Natural selenium was thermally dissociated in a quartz resonance cell keeping the background pressure of abundant selenium molecules low by differential heating. The 4p35s5S2 level was excited by frequency-tripled pulsed-dye laser radiation at 207 nm. From time-resolved recordings of the fluorescence decay at 216 nm a natural radiative lifetime of 493(15) ns was determined, while quantum-beat and optical double-resonance measurements in an external magnetic field yielded g(J) = 2.0004(10) for the Lande factor. The results are compared with previous theoretical and experimental data.
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| 4. |
- Berzinsh, U, et al.
(författare)
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Radiative lifetimes for the 4p excited states of phosphorus and the oscillator strengths of solar lines
- 1997
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Ingår i: Astronomy & Astrophysics. - 0004-6361. ; 326:1, s. 412-416
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes for the levels of the 3s(2)3p(2)4p configuration in neutral phosphorus have been determined experimentally for the first time and also theoretically. Experiments were performed by using two-photon UV laser excitation and subsequent fluorescence detection in a laser-produced plasma. In relativistic Hartree-Fock calculations, the Cowan code extended to 42 configurations was used. Finally, the lifetimes for all the 13 excited states in the 4p configuration were calculated and for 6 of them the values were measured experimentally. Theoretical branching ratios were combined with experimental lifetimes, to deduce oscillator strengths and these were used for the evaluation of the phosphorus abundance in the sun. A value of 5.49 (0.04) was obtained in the usual logarithmic scale.
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| 5. |
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| 6. |
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| 7. |
- Luo, C. Y, et al.
(författare)
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Determination of Radiative Lifetimes of Neutral Bismuth By Time-resolved Uv-vuv Laser Spectroscopy
- 1995
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 52:3, s. 1936-1941
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Tidskriftsartikel (refereegranskat)abstract
- Time-resolved laser spectroscopy was used to measure natural radiative lifetimes of ten excited states of neutral bismuth. Four levels of the 6p(2)ns (4)p(1/2) sequence (n = 7,8,9,10) and the 6p(2)7s P-4(3/2),(5/2) and 6p(2)nd(2)D(2/3;5/2) (n = 6,7) levels were investigated. The results are compared with previous data when possible. Revised absolute transition probabilities for 26 lines are given. Several levels required vacuum-ultraviolet (vuv) excitation, which was achieved by stimulated anti-Stokes Raman shifting of frequency-tripled dye-laser radiation in high-pressure H-2 gas.
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| 8. |
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| 9. |
- Zerne, R, et al.
(författare)
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Oscillator strengths of sulphur 3s(2) 3p(3) 4s S-3(0)-3s(2) 3p(3) 4p P-3 transitions measured by time resolved two-photon laser spectroscopy
- 1997
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Ingår i: Physica Scripta. Topical Issues. - : IOP Publishing. - 0281-1847. ; 56:5, s. 459-461
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Tidskriftsartikel (refereegranskat)abstract
- Oscillator strengths for the three 3s(2)3p(3)4s S-3(1)o-3s(2)3p(3)4p P-3(0,1,2) transitions in neutral sulphur have been determined directly from lifetime measurements. Two-photon UV laser excitation and subsequent fluorescence detection have been used on atoms produced in a thermal sulphur beam or in a laser-driven plasma. A good agreement was found between data obtained in both schemes. The lifetime data obtained, tau(P-3(0)) = 46.1(1.0) ns, tau(P-3(1)) = 46.1(1.0) ns and tau(P-3(2)) = 46.1(1.0) ns are compared with results of theoretical and experimental data from literature. The absorption oscillator strengths derived are f(S-3(1)o-P-3(0)) = 0.120(0.003), f(S-3(1)o-P-3(1)) = 0.360(0.008) and f(S-3(1)o-P-3(2)) = 0.600(0.013), respectively. For the next higher member of the series, 3s(2)3p(3)5p P-3(1,2), a substantially longer Lifetime, 188(13) ns, was obtained.
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| 10. |
- Zerne, R, et al.
(författare)
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Radiative Lifetimes In Neutral Tellurium Measured By Time-resolved Laser Spectroscopy
- 1994
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Ingår i: Zeitschrift für Physik D Atoms, Molecules and Clusters. - 0178-7683. ; 32:1-2, s. 31-34
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of natural radiative lifetimes in atomic tellurium in the 5 p(3)7p configuration are reported. Two-step laser excitation was applied on tellurium vapour in a cell that was differentially heated and pumped through a capillary. The decay of the fluorescence signal was recorded at different vapour pressures. The following four radiative lifetime values were obtained: 7p P-5(1): 128(11) ns, 7p P-5(2): 99(8) ns, 7p P-3(1): 82(10) ns and 7p P-3(2): 124(8) ns.
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