| 1. |
- Li, Z. S, et al.
(författare)
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The FERRUM project: radiative lifetimes of intermediate-excitation states of Fe II measured in a fluorescence signal induced by laser pumping from a metastable state
- 1999
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 6:1, s. 9-12
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Tidskriftsartikel (refereegranskat)abstract
- A new collaborative program, the FERRUM project. aims at extending and improving the database of oscillator strengths for the astrophysical important Fe II spectrum. In this paper we report on the experimental method applied for measurements of radiative lifetimes of Fe II levels at intermediate excitation (5-10 eV) that can be populated ba laser excitation from metastable states. The technique involves a laser-produced plasma as a source for metastable ions, a stimulated Brillouin scatttering cell for shortening the laser pulse, and fast time resolved detection. We have applied the technique on two Fe II levels at about 7.5 eV and obtained the lifetimes: tau(z(4)S(3/2)(0)) = 3.8(2) ns; tau(y(4)P(5/2)(0)) = 3.6(3) Its.
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| 2. |
- Li, Z. S, et al.
(författare)
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Determination of radiative lifetimes of neutral sulphur by time-resolved three-photon VUV laser spectroscopy
- 1998
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 2:1, s. 11-14
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes of the highly exited states 3p(3)8s S-3(1)0 and 3p(3)6d D-3(1,2,3)0 of neutral sulphur have been measured using time-resolved laser-induced fluorescence. The sulphur atoms were generated in a laser-produced plasma. The investigated states were populated through a two-step process involving a two-photon excitation to the lowest excited tripler state of even parity 3p(4) P-3(0,1,2), followed by a one-photon excitation to the investigated state. We obtained tau(8s(3)S(1)(0)) = 40 +/- 5 ns and tau(6d(3)D(1,2,3)(0)) = 75 +/- 7 ns. These values are much longer than theoretically predicted ones and much shorter than those indirectely inferred from astronomical data.
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