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See detailImproved atomic data for iridium atom (Ir I) and ion (Ir II) and the solar content of iridium
Xu, H. L.; Svanberg, S.; Quinet, Pascal ULg et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2007), 104(1), 52-70

From a combination of radiative lifetime measurements, performed with a time-resolved laser-induced fluorescence technique, for nine odd-parity levels of Ir I and four odd-parity levels of Ir 11 and ... [more ▼]

From a combination of radiative lifetime measurements, performed with a time-resolved laser-induced fluorescence technique, for nine odd-parity levels of Ir I and four odd-parity levels of Ir 11 and branching fraction calculations, extended sets of transition probabilities have been derived for transitions of astrophysical interest. The new results are compared with the few experimental data available in the literature and a good agreement is found. They extend considerably the previous sets of transition probabilities available in the literature. Implications of the new results regarding the solar content of iridium are briefly discussed. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailRadiative lifetime measurements and semi-empirical transition probability calculations in neutral rhenium
Palmeri, P.; Quinet, Pascal ULg; Biémont, Emile ULg et al

in Physica Scripta (2006), 74(3), 297-303

Radiative lifetimes of 11 odd-parity levels of neutral rhenium (Re I) were measured using time-resolved laser-induced fluorescence techniques. For ten levels, there were no previous results available. The ... [more ▼]

Radiative lifetimes of 11 odd-parity levels of neutral rhenium (Re I) were measured using time-resolved laser-induced fluorescence techniques. For ten levels, there were no previous results available. The new results have been used to assess the accuracy of calculations with a Hartree-Fock-plus-relativistic-corrections model that takes configuration interaction and core-polarization effects into account and they have allowed the deduction of reliable semi-empirical transition probabilities for 81 Re I lines. [less ▲]

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See detailRadiative lifetimes and transition probabilities of astrophysical interest in ZrII
Malcheva, G.; Blagoev, K.; Mayo, R. et al

in Monthly Notices of the Royal Astronomical Society (2006), 367(2), 754-762

Radiative lifetimes of 16 odd levels belonging to the 4d(2)5p configuration of Zr II have been measured using a time-resolved laser-induced fluorescence technique with a single-step excitation process ... [more ▼]

Radiative lifetimes of 16 odd levels belonging to the 4d(2)5p configuration of Zr II have been measured using a time-resolved laser-induced fluorescence technique with a single-step excitation process either from the ground state or from metastable levels belonging to the 4d(2)5s and 4d(3) configurations. For 12 levels, there were no previous results available. The new experimental results and the lifetime values available in the literature have allowed to test a theoretical relativistic Hartree-Fock (HFR) model including core-polarization effects and to deduce transition probabilities for 242 transitions of astrophysical interest in the range 187.8-535.0 nm. [less ▲]

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See detailTransition probabilities and lifetimes in neutral and singly ionized osmium and the Solar osmium abundance
Quinet, Pascal ULg; Palmeri, P.; Biémont, Emile ULg et al

in Astronomy and Astrophysics (2006), 448(3), 1207-93

Radiative lifetime measurements have been performed, with a time-resolved laser-induced fluorescence technique, for 12 levels of Os I and for 9 levels of Os II. For 9 levels of Os I and 4 levels of Os II ... [more ▼]

Radiative lifetime measurements have been performed, with a time-resolved laser-induced fluorescence technique, for 12 levels of Os I and for 9 levels of Os II. For 9 levels of Os I and 4 levels of Os II, there were no previous experimental data available. From a comparison with new theoretical calculations, taking configuration interactions and core-polarization effects into account, it has been possible to deduce oscillator strengths for 129 transitions of Os I and 137 transitions of Os II of astrophysical interest appearing in the wavelength range 180.0-870.0 nm. These results have allowed us to revise the abundance of osmium in the solar photosphere (log epsilon(Os) = 1.25 +/- 0.11). The newly derived oscillator strengths have been applied as well to derive the osmium abundance in the carbon-rich metal-poor star HD 187861. [less ▲]

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See detailRadiative lifetimes and transition probabilities in TaI
Fivet, V.; Palmeri, P.; Quinet, Pascal ULg et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2006), 37(1), 29-35

Radiative lifetimes of 14 odd-parity Ta I levels, belonging to the 5d(3)6s6p and 5d(4)6p configurations in the energy range from 30 664 to 45 256 cm(-1). have been measured using the time-resolved laser ... [more ▼]

Radiative lifetimes of 14 odd-parity Ta I levels, belonging to the 5d(3)6s6p and 5d(4)6p configurations in the energy range from 30 664 to 45 256 cm(-1). have been measured using the time-resolved laser-induced fluorescence technique. Extensive calculations, taking configuration interactions and corepolarisation effects into account, are able to reproduce in a satisfying way the available experimental results but suffer from the rather fragmentary knowledge of the level structure of this atom. New transition probabilities are deduced for a set of strong lines depopulating the levels investigated experimentally in the present work. [less ▲]

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See detailLifetimes along perturbed Rydberg series in neutral thallium
Biémont, Emile ULg; Palmeri, P.; Quinet, Pascal ULg et al

in Journal of Physics B-Atomic Molecular and Optical Physics (2005), 38(19), 3547-3558

Radiative lifetimes of 15 Tl I levels belonging to the 6s(2)ns(2)S(1/2) (n = 7-14) and 6s(2)nd(2)D(3/2) Rydberg series (n = 6-12) have been measured using a time-resolved laser-induced fluorescence ... [more ▼]

Radiative lifetimes of 15 Tl I levels belonging to the 6s(2)ns(2)S(1/2) (n = 7-14) and 6s(2)nd(2)D(3/2) Rydberg series (n = 6-12) have been measured using a time-resolved laser-induced fluorescence technique. All the measured levels have been excited from the ground state 6s(2)6p(2)P(1/2)(0) (odd parity) with a single-step excitation process. The general perturbation of the ns series by the 6s6p(2) configuration and the corresponding modification of the lifetimes are adequately reproduced by a theoretical model including core-polarization effects and combined with a least-squares fit to the observed energy levels. The general behaviour of the lifetime values for the 6s(2)np odd levels along the Rydberg series is also well reproduced. The use of the multiconfiguration quantum defect theory has allowed us to obtain lifetime values along the 6s(2)ns(2)S(1/2) series up to levels with n = 31. [less ▲]

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See detailTransition probabilities and lifetimes in singly ionized rhenium
Palmeri, P.; Quinet, Pascal ULg; Biémont, Emile ULg et al

in Monthly Notices of the Royal Astronomical Society (2005), 362(4), 1348-1352

Transition probabilities and radiative lifetimes have been obtained for 45 transitions of Re II using a combination of radiative lifetime values obtained with the laser-induced fluorescence technique ... [more ▼]

Transition probabilities and radiative lifetimes have been obtained for 45 transitions of Re II using a combination of radiative lifetime values obtained with the laser-induced fluorescence technique ( seven levels) and theoretical branching fractions. This new set of results, concerning ultraviolet and visible lines, will be useful in the future for investigating the composition of chemically peculiar stars. [less ▲]

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See detailRadiative lifetime and transition probabilities in CdI and CdII
Xu, H. L.; Persson, A.; Svanberg, S. et al

in Physical Review A (2004), 70(4), 1-14

Radiative lifetimes of 11 levels belonging to the 5s5p P-1(1)o 5snd D-3(1,2) (n=6-9) and 5sns S-3(1) (n=7,8) series of Cd I, and of 5 levels of Cd II (i.e., 4d(10)5p P-2(1/2.3/2)o, 4d(10)6s S-2(1/2), and ... [more ▼]

Radiative lifetimes of 11 levels belonging to the 5s5p P-1(1)o 5snd D-3(1,2) (n=6-9) and 5sns S-3(1) (n=7,8) series of Cd I, and of 5 levels of Cd II (i.e., 4d(10)5p P-2(1/2.3/2)o, 4d(10)6s S-2(1/2), and 4d(10)5d D-2(3/2,5/2)) have been measured using the time-resolved laser-induced fluorescence technique. Free neutral and singly ionized cadmium atoms have been generated by laser ablation. Single- or two-step excitation processes were considered to populate the levels under study. Branching fractions of Cd II transitions have been measured by laser-induced breakdown spectroscopy. Transition probabilities and oscillator strengths for Cd I and Cd II spectral lines originating from the above states as well as from the 4d(9)5 s(22)D(3/2,5/2) states of Cd II have been deduced by combining the experimental lifetimes and theoretical branching fractions obtained in multiconfigurational relativistic Hartree-Fock calculations taking core-polarization effects into account. [less ▲]

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See detailRadiative lifetimes of Zn I, II excited states
Blagoev, K. B.; Malcheva, G.; Penchev, V. et al

in Physica Scripta (2004), 69(6), 433-440

Radiative lifetimes of excited states of Zn I (3d(10)4sns S-3(1), n = 6-8; 3d(10) 4snd D-3, n = 4-7) and Zn II (3d(10) 4p P-2(1/2.3/2), 4d D-2(3/2,5/2), 3d(10)5S S-2(1/2)) have been measured using a time ... [more ▼]

Radiative lifetimes of excited states of Zn I (3d(10)4sns S-3(1), n = 6-8; 3d(10) 4snd D-3, n = 4-7) and Zn II (3d(10) 4p P-2(1/2.3/2), 4d D-2(3/2,5/2), 3d(10)5S S-2(1/2)) have been measured using a time-resolved laser-induced fluorescence technique. Single- or two-step excitation of atoms and ions produced by laser ablation was employed. The experimental radiative lifetimes have been compared with theoretical results obtained within a multiconfigurational relativistic Hartree-Fock approach taking core-polarization effects into account. [less ▲]

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See detailExperimental lifetime determination in neutral praseodymium (Pr I) and neodymium (Nd I)
Biémont, Emile ULg; Quinet, Pascal ULg; Svanberg, S. et al

in Journal of Physics B-Atomic Molecular and Optical Physics (2004), 37(7), 1381-1389

Radiative lifetime measurements have been performed, with a time-resolved laser-induced fluorescence technique, for 18 even-parity levels of Pr I and 15 odd-parity levels of Nd I. The new results are ... [more ▼]

Radiative lifetime measurements have been performed, with a time-resolved laser-induced fluorescence technique, for 18 even-parity levels of Pr I and 15 odd-parity levels of Nd I. The new results are compared with the few experimental data available in the literature and good agreement is found. However, fragmentary knowledge of the spectra prevents reliable calculation of branching fractions and calls for additional laboratory efforts in order to provide the astrophysicists with reliable transition probabilities needed for investigating the magnetic fields in chemically peculiar stars. [less ▲]

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See detailRadiative lifetimes of Cd I and Cd II excited states
Xu, H.; Persson, A.; Svanberg, S. et al

Conference (2004)

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See detailTime-resolved laser-induced fluorescence lifetime measurements and relativistic Hartree-Fock calculations of transition probabilities in SmII
Xu, H. L.; Svanberg, S.; Quinet, Pascal ULg et al

in Journal of Physics B-Atomic Molecular and Optical Physics (2003), 36(24), 4773-4787

Radiative lifetime measurements were performed with time-resolved laser-induced fluorescence techniques for 47 levels of the astrophysically important ion Sm1+ over the energy range 21000-36 000 cm(-1 ... [more ▼]

Radiative lifetime measurements were performed with time-resolved laser-induced fluorescence techniques for 47 levels of the astrophysically important ion Sm1+ over the energy range 21000-36 000 cm(-1). The new results have been compared with previous measurements but also with theoretical calculations taking configuration interactions and core-polarization effects into account, and a satisfying agreement has been found for many levels of this complex ion. New calculated transition probabilities are deduced from the experimental lifetimes and from the theoretical branching fractions for 162 transitions of astrophysical interest. These results will help astrophysicists in the quantitative investigation of the chemical composition of CP stars. [less ▲]

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See detailTheoretical and experimental lifetime determination in singly ionized neodymium (Nd II)
Xu, H. L.; Svanberg, S.; Cowan, R. D. et al

in Monthly Notices of the Royal Astronomical Society (2003), 346(2), 433-440

Radiative lifetime measurements were performed with time-resolved laser-induced fluorescence techniques for 24 levels of Nd II in the energy range 20 500- 32 500 cm(-1). For 17 levels, no previous ... [more ▼]

Radiative lifetime measurements were performed with time-resolved laser-induced fluorescence techniques for 24 levels of Nd II in the energy range 20 500- 32 500 cm(-1). For 17 levels, no previous experimental data exist. These results have allowed the testing of new theoretical calculations with the relativistic Hartree-Fock method taking configuration interactions and core-polarization effects into account, and a satisfying agreement has been found for this complex ion. A new set of calculated oscillator strengths, accurate within a few per cent for the strongest transitions, is presented for 107 lines of astrophysical interest appearing in the wavelength range 358.0-1100.0 nm. These results will be useful to evaluate abundance values of neodymium in chemically peculiar stars in relation with cosmochronology. [less ▲]

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See detailRadiative lifetime measurements and oscillator strength determination for transitions in singly ionized praseodymium (Pr II)
Biémont, Emile ULg; Lefèbvre, P.-H.; Quinet, Pascal ULg et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2003), 27(1), 33-41

New radiative lifetimes for 20 levels of Pr II have been measured using the time-resolved laser-induced fluorescence (LIF) technique. The combination of these experimental values with theoretical ... [more ▼]

New radiative lifetimes for 20 levels of Pr II have been measured using the time-resolved laser-induced fluorescence (LIF) technique. The combination of these experimental values with theoretical branching fractions (BF) obtained with the pseudo-relativistic Hartree-Fock (HFR) approach has allowed us to determine oscillator strengths and transition probabilities for about 150 lines appearing in the spectral region between 369.9 and 741.2 nm. A detailed discussion of our new results and comparisons with previous data are also given in the present paper. [less ▲]

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See detailRadiative lifetime measurements in ErII by time-resolved laser spectroscopy
Xu, H. L.; Jiang, Z. K.; Zhang, Z. G. et al

in Journal of Physics B-Atomic Molecular and Optical Physics (2003), 36(9), 1771-1781

Radiative lifetimes of 30 excited states of Er 11, ranging in energy from 25 592 to 36 148 cm(-1), have been measured by means of a time-resolved laser-induced fluorescence (LIF) technique. Free, singly ... [more ▼]

Radiative lifetimes of 30 excited states of Er 11, ranging in energy from 25 592 to 36 148 cm(-1), have been measured by means of a time-resolved laser-induced fluorescence (LIF) technique. Free, singly ionized erbium ions were produced in a laser-induced plasma. A tunable laser, with 1 ns duration pulse, was employed to selectively excite the Er+ ions. The lifetime values were evaluated from the transient LIF signals recorded by a fast detection system. A comparison of the new results with previously published values is given. HFR calculations, including core-polarization contributions, are found to be in reasonable agreement with experiment, but the present calculations clearly indicate that further laboratory and theoretical work is urgently needed, particularly for the low lying odd configurations of this complex ion. [less ▲]

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See detailTime-resolved laser-induced fluorescence measurements of Rydberg states in Lu I and comparison with theory
Dai, Z. W.; Jiang, Z. K.; Xu, H. L. et al

in Journal of Physics B-Atomic Molecular and Optical Physics (2003), 36(3), 479-487

Time-resolved laser-induced fluorescence measurements have been performed for ten odd Rydberg states of neutral lutetium, belonging to the 6s(2)(S-1)np(n = 8-9) and 6 s(2)(S-1)nf (n = 5-8) series. For 6S ... [more ▼]

Time-resolved laser-induced fluorescence measurements have been performed for ten odd Rydberg states of neutral lutetium, belonging to the 6s(2)(S-1)np(n = 8-9) and 6 s(2)(S-1)nf (n = 5-8) series. For 6S(2)(S-1)8p and 6s(2)(S-1)7f, the experimental lifetimes corresponding to the two J values within the doublet differ substantially. Comparison with theoretical values, calculated with extensive configuration interaction and core-polarization effects included, shows that the experimental trends are adequately reproduced both for np (n = 8-9) and nf (n = 5-8) states. [less ▲]

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See detailRadiative lifetime and oscillator strength determinations in SmIII
Biémont, Emile ULg; Garnir, Henri-Pierre ULg; Litzen, U. et al

in Astronomy and Astrophysics (2003), 399(1), 343-349

Radiative lifetimes of 6 levels belonging to the 4f(5)((6)Hdegrees, (6)Fdegrees)5d configuration of Sm III have been measured for the first time using a time-resolved laser-induced fluorescence technique ... [more ▼]

Radiative lifetimes of 6 levels belonging to the 4f(5)((6)Hdegrees, (6)Fdegrees)5d configuration of Sm III have been measured for the first time using a time-resolved laser-induced fluorescence technique. Experimental data have been compared with semi-empirical calculations. The agreement is excellent for 4 levels with (6)Fdegrees as a parent term. Larger discrepancies (53 and 37%) are observed for 2 levels with (6)Hdegrees and (6)Fdegrees, respectively, as a parent term and are explainable by strong mixing and cancellation effects occurring in the line strength calculations which are responsible of "instabilities" occurring in the lifetimes considered as a function of J value within the term. Branching ratios for the lines depopulating the levels of interest have been measured by Fourier transform spectroscopy. A first set of oscillator strengths has been deduced for this ion. [less ▲]

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See detailLifetime measurements and calculations in singly ionized ytterbium
Biémont, Emile ULg; Quinet, Pascal ULg; Dai, Z. W. et al

in Journal of Physics B-Atomic Molecular and Optical Physics (2002), 35(22), 4743-4749

New radiative lifetimes, measured by time-resolved laser-induced fluorescence spectroscopy, are reported for five Rydberg states of singly ionized ytterbium. Free Yb+ ions were produced in a laser-induced ... [more ▼]

New radiative lifetimes, measured by time-resolved laser-induced fluorescence spectroscopy, are reported for five Rydberg states of singly ionized ytterbium. Free Yb+ ions were produced in a laser-induced plasma. The experimental results have been compared with HFR calculations, taking core-polarization effects into account, and a good agreement (within 25%) between theory and experiment is observed for four levels. HFR results are also proposed for np (n less than or equal to 7) and nf (n less than or equal to 8) Rydberg states and compared with available data. [less ▲]

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See detailRadiative lifetime measurements and transition probability calculations in lanthanide ions
Quinet, Pascal ULg; Palmeri, P.; Biémont, Emile ULg et al

in Journal of Alloys and Compounds (2002), 344(1-2), 255-259

We have undertaken a systematic investigation of spectroscopic properties of lanthanide ions (Z=57-71). Using time-resolved laser-induced fluorescence following one- or two-photon excitations, a large ... [more ▼]

We have undertaken a systematic investigation of spectroscopic properties of lanthanide ions (Z=57-71). Using time-resolved laser-induced fluorescence following one- or two-photon excitations, a large number of radiative lifetimes have been measured at the Lund Laser Centre for singly, doubly and trebly ionized atoms. These new measurements have been used for testing theoretical calculations performed within the framework of a relativistic Hartree-Fock approach taking core-polarization effects into account. Using the experimental lifetimes (when available) and the theoretical branching fractions, a large number of transition probabilities, most of them of astrophysical interest, have been deduced and are stored in a new database (DREAM). Up to now, the results obtained concern the following ions: La2+, Ce2+, Ce2+, Pr2+, Ho2+, Er2+, Tm2+, Tm2+, Yb2+, Yb2+, Yb2+, Lu2+ and Lu2+. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailRadiative lifetimes of 6sns S-3(1) and 6snd D-3(1) excited states of HgI
Blagoev, K.; Pentchev, V.; Biémont, Emile ULg et al

in Physical Review A (2002), 66(3),

Natural radiative lifetimes have been measured along the 6sns S-3(1) (n=7-10) and 6snd D-3(1) (n=6-11) Rydberg series of neutral mercury using time-resolved laser-induced fluorescence spectroscopy in a ... [more ▼]

Natural radiative lifetimes have been measured along the 6sns S-3(1) (n=7-10) and 6snd D-3(1) (n=6-11) Rydberg series of neutral mercury using time-resolved laser-induced fluorescence spectroscopy in a laser-produced mercury plasma. The states of Hg I investigated in the present work were populated from the ground state by a stepwise excitation process. Relativistic Hartree-Fock calculations, including intravalence interactions and core-polarization effects, have been performed and the theoretical lifetimes have been compared with the measurements. [less ▲]

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