References of "Biémont, Emile"
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See detailRelativistic Hartree-Fock and Dirac-Fock atomic structure calculations in Fr-like ions Ra+, Ac2+Th3+ and U5+
Biémont, Emile ULg; Fivet, V.; Quinet, Pascal ULg

in Journal of Physics B-Atomic Molecular and Optical Physics (2004), 37(20), 4193-4204

A detailed investigation of radiative parameters for electric dipole (El) transitions is presented for the ions Ra II, Ac 111, Th IV and U VI along the francium isoelectronic sequence. The pseudo ... [more ▼]

A detailed investigation of radiative parameters for electric dipole (El) transitions is presented for the ions Ra II, Ac 111, Th IV and U VI along the francium isoelectronic sequence. The pseudo-relativistic Hartree-Fock (BFR) method including core-polarization effects is used for the calculations. Comparisons with multiconfigurational Dirac-Fock (MCDF) calculations show that the most important relativistic effects are taken into account. In view of their importance in nuclear laser spectroscopy, forbidden rates (transitions M1 and E2) in Th IV are also reported in this paper. [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 detailOn the importance of an M2 depopulating channel for a KrII metastable state
Biémont, Emile ULg; Derkatch, A.; Lundin, P. et al

in Physical Review Letters (2004), 93(6),

An experimental investigation of the radiative lifetime of the metastable 4s(2)4p(4)(P-3)4d D-4(7/2) level in Kr II shows an unusual situation regarding the importance of an M2 depopulation channel. While ... [more ▼]

An experimental investigation of the radiative lifetime of the metastable 4s(2)4p(4)(P-3)4d D-4(7/2) level in Kr II shows an unusual situation regarding the importance of an M2 depopulation channel. While the first order M1 and E2 channels are expected to contribute in a dominant way to the decay, the experimental result, obtained using a laser probing technique on a stored ion beam, tau=0.57+/-0.03 s, is far too short to be due to these channels according to our relativistic multiconfiguration Dirac-Fock calculation. Only if second order contributions to the decay branches (including essentially the M2 contribution) are taken into account in the calculations could the unexpected short lifetime be explained. [less ▲]

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See detailLande g-factors for experimentally determined energy levels in doubly ionized lanthanides
Quinet, Pascal ULg; Biémont, Emile ULg

in Atomic Data and Nuclear Data Tables (2004), 87(2), 207-230

Lande g-factors have been calculated for over 1500 energy levels of doubly ionized lanthanides (Z = 57-71). Configuration interaction and relativistic effects have been included in the computations using ... [more ▼]

Lande g-factors have been calculated for over 1500 energy levels of doubly ionized lanthanides (Z = 57-71). Configuration interaction and relativistic effects have been included in the computations using the relativistic Hartree-Fock (HFR) technique combined with a least-squares fitting of the Hamiltonian eigenvalues to the observed energy levels. These new results are compared with previous experimental and theoretical values when available. (C) 2004 Elsevier Inc. All rights reserved. [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 detailLifetimes of metastable levels in ArII
Schef, P.; Derkatch, A.; Lundin, P. et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2004), 29(2), 195-199

We report on a calculation of five lifetimes of metastable levels in Ar II, obtained with a relativistic Hartree-Fock method in which most of the intravalence correlation is represented within a ... [more ▼]

We report on a calculation of five lifetimes of metastable levels in Ar II, obtained with a relativistic Hartree-Fock method in which most of the intravalence correlation is represented within a configuration interaction scheme while core-valence correlation is described by a core-polarization model potential with a core-penetration corrective term. The quality of the calculation has been assessed through an experimental determination of the radiative lifetime of the metastable 3d(4)F(9/2) level. The experiment was performed with a laser probing technique on a stored ion beam at the CRYRING of Stockholm. [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 detailL'astronomie en Europe à la fin du XVIIIè siècle (1789-1802)
Biémont, Emile ULg

Conference (2004)

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See detailAstronomes célèbres et astronomes moins connus ... (4) Bailly
Biémont, Emile ULg

in Galactée (2004), 40

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See detailAstronomes célèbres et astronomes moins connus ... (5) Hubble
Biémont, Emile ULg

in Galactée (2004), 43

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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 detailHyperfine structure for neutral manganese lines of astrophysical interest
Lefèbvre, P.-H.; Garnir, Henri-Pierre ULg; Biémont, Emile ULg

in Astronomy and Astrophysics (2003), 404(3), 1153-1158

The hyperfine structure of 40 levels of neutral manganese has been studied by means of Fourier transform emission spectroscopy. The light source was a home-made 99.5% pure manganese hollow-cathode lamp ... [more ▼]

The hyperfine structure of 40 levels of neutral manganese has been studied by means of Fourier transform emission spectroscopy. The light source was a home-made 99.5% pure manganese hollow-cathode lamp. From the analysis of the line profiles observed in the visible and infrared regions, we have been able to deduce new magnetic dipole constants for 18 levels and to revise previous results for 22 additional levels. [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 detailLifetimes, oscillator strengths and Lande factors in doubly ionized europium (Eu III)
Quinet, Pascal ULg; Biémont, Emile ULg

in Monthly Notices of the Royal Astronomical Society (2003), 340(2), 463-467

A set of transition probabilities has been calculated for Eu iii transitions of astrophysical interest particularly for the study of chemically peculiar stars. They were obtained taking configuration ... [more ▼]

A set of transition probabilities has been calculated for Eu iii transitions of astrophysical interest particularly for the study of chemically peculiar stars. They were obtained taking configuration interaction and core-polarization effects into account. The accuracy of the new scale of oscillator strengths, which differs substantially from previous results, has been assessed through comparisons with recent time-resolved laser-induced fluorescence measurements of radiative lifetimes. [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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