| 1. |
- Hartman, Henrik, et al.
(författare)
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The FERRUM project: an extremely long radiative lifetime in Ti II measured in an ion storage ring
- 2003
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 36, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- We have extended the laser probing technique at the CRYRING storage ring to measurement of the extremely long lifetime (28 s) of the metastable 3d2(3P)4s b 4P5/2 level in Ti II. The result obtained demonstrates the power of this method for investigation of such long-lived levels. This is the first experimental lifetime investigation of metastable states in Ti II.
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| 2. |
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| 3. |
- Hartman, Henrik, et al.
(författare)
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The FERRUM Project: Experimental transition probabilities of [Fe II] and astrophysical applications
- 2003
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 397:3, s. 1143-1149
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Tidskriftsartikel (refereegranskat)abstract
- We report on experimental transition probabilities for thirteenforbidden [Fe II] lines originating from three different metastable FeIi levels. Radiative lifetimes have been measured of two metastablestates by applying a laser probing technique on a stored ion beam.Branching ratios for the radiative decay channels, i.e. M1 and E2transitions, are derived from observed intensity ratios of forbiddenlines in astrophysical spectra and compared with theoretical data. Thelifetimes and branching ratios are combined to derive absolutetransition probabilities, A-values.We present the first experimental lifetime values for the two Fe IIlevels a4G9/2 and b2H11/2and A-values for 13 forbidden transitions froma6S5/2, a4G9/2 andb4D7/2 in the optical region. A discrepancybetween the measured and calculated values of the lifetime for theb2H11/2 level is discussed in terms of levelmixing. We have used the code CIV3 to calculate transitionprobabilities of the a6D-a6S transitions.We have also studied observational branching ratios for lines from 5other metastable Fe II levels and compared them to calculated values. Aconsistency in the deviation between calibrated observational intensityratios and theoretical branching ratios for lines in a wider wavelengthregion supports the use of [Fe II] lines for determination of reddening.
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| 4. |
- Rostohar, D, et al.
(författare)
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Studies of lifetimes in an ion storage ring using laser technique
- 2003
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Ingår i: Hyperfine Interactions. - 1572-9540 .- 0304-3843. ; 146:1-4, s. 151-159
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Konferensbidrag (refereegranskat)abstract
- The laser-probing method for lifetime measurements of metastable levels, performed by applying the Fast Ion Beam Laser (FIBLAS) method to ions stored in a storage ring, has been developed by the Stockholm group. Recently, we have applied this method to lifetime measurements of close lying metastable levels. In this paper we discuss experimental studies of ions with complex structure and present the first experimentally obtained lifetimes of selected metastable levels in complex systems as Fe+, Eu+ and La+.
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