References of "Biémont, Emile"
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See detailRecent advances in the study of lanthanide atoms and ions
Biémont, Emile ULg; Quinet, Pascal ULg

in Physica Scripta (2003), T105

We present an overview of the recent developments concerning the spectroscopic properties of lanthanide atoms and ions (Z = 57-71). This review is focussed on the advances made during the past twenty ... [more ▼]

We present an overview of the recent developments concerning the spectroscopic properties of lanthanide atoms and ions (Z = 57-71). This review is focussed on the advances made during the past twenty years regarding the analysis of the spectra, the transition probabilities, the radiative lifetimes and also the hyperfine structures and isotope shifts. Theoretical aspects as well as experimental measurements are both covered in this paper including bibliographical references up to the end of 2001. Some astrophysical implications of the new atomic data concerning the chemical composition of the sun are briefly reviewed. Emphasis is also put on the new database D.R.E.A.M. developed on a web site of Mons University in Belgium. [less ▲]

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See detailAstronomes célèbres et astronomes moins connus ... (2) Les Cassini
Biémont, Emile ULg

in Galactée (2003), 35

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See detailX-Ray spectromicroscopy of clusters heated by fs laser radiation
Faenov, A.Ya.; Magunov, A. I.; Pikuz, T. A. et al

Conference (2003)

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See detailAstronomes célèbres et astronomes moins connus ... (3) Hipparque
Biémont, Emile ULg

in Galactée (2003), 35

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See detailAstronomes célèbres et astronomes moins connus ... (1) William Herschel
Biémont, Emile ULg

in Galactée (2003), 34

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See detailEvolution of time measurement in Astronomy
Biémont, Emile ULg

in Heck, A. (Ed.) Information Handling in Astronomy - Historical Vistas (2003)

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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 detailCore-polarization effects in doubly ionized cerium (Ce III) for transitions of astrophysical interest
Biémont, Emile ULg; Quinet, Pascal ULg; Ryabchikova, T. A.

in Monthly Notices of the Royal Astronomical Society (2002), 336(4), 1155-1160

The importance of core-polarization effects on oscillator strength determination in Ce III is emphasized. The inclusion of these effects in relativistic Hartree-Fock (HFR) calculations leads to ... [more ▼]

The importance of core-polarization effects on oscillator strength determination in Ce III is emphasized. The inclusion of these effects in relativistic Hartree-Fock (HFR) calculations leads to theoretical lifetime values for some 4f6p levels of this ion in close agreement with recent time-resolved laser-induced fluorescence measurements. These new atomic data, the most accurate to date, have allowed the refinement of the stellar abundance determination of cerium in the chemically peculiar star HD 192913, but have not altered in a drastic way the conclusions derived in recent analyses regarding the overabundance of this element. [less ▲]

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See detailCerium: The lithium substitute in post-AGB stars
Reyniers, M.; Winckel, H. V.; Biémont, Emile ULg et al

in Astronomy and Astrophysics (2002), 395(2), 35-38

In this letter we present an alternative identification for the line detected in the spectra of s-process enriched low-mass post-AGB stars around 6708 Angstrom and which was interpreted in the literature ... [more ▼]

In this letter we present an alternative identification for the line detected in the spectra of s-process enriched low-mass post-AGB stars around 6708 Angstrom and which was interpreted in the literature as due to Li. Newly released line lists of lanthanide species reveal, however, the likely identification of the line to be due to a Ce II transition. We argue that this identification is consistent with the Ce abundance of all the objects discussed in the literature and conclude that in none of the low-mass s-process enriched post-AGB stars there is indication for Li-production. [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 detailTransition probabilities in GdIII
Biémont, Emile ULg; Kohnen, G.; Quinet, Pascal ULg

in Astronomy and Astrophysics (2002), 393(2), 717-720

Theoretical lifetimes, calculated with inclusion of core-polarization effects, have been determined for five 4f(7) 6p levels of doubly ionized gadolinium. They agree quite well with recent experimental ... [more ▼]

Theoretical lifetimes, calculated with inclusion of core-polarization effects, have been determined for five 4f(7) 6p levels of doubly ionized gadolinium. They agree quite well with recent experimental values measured by time-resolved laser-induced fluorescence spectroscopy. From this agreement, the accuracy of a first set of Gd III transition probabilities, calculated for 4f(7) 5d- 4f(7) 6p and 4f(7) 6s- 4f(7) 6p transitions of astrophysical interest, has been assessed. [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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See detailLevel lifetimes in 3p and 3d configurations of Fe XII
Biémont, Emile ULg; Palmeri, P.; Quinet, Pascal ULg et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2002), 20(1), 37-44

Transitions between the five fine-structure levels in the 3s(2)3p(3) ground configuration of Fe XII (P-like) are of interest in astrophysics and terrestrial plasma diagnostics. The decay rates give rise ... [more ▼]

Transitions between the five fine-structure levels in the 3s(2)3p(3) ground configuration of Fe XII (P-like) are of interest in astrophysics and terrestrial plasma diagnostics. The decay rates give rise to level lifetimes in the millisecond range, which have been measured recently at a heavy-ion storage ring. While most of the 3s(2)3p(2)3d levels are short-lived, two of these levels have no El decay channels and may also have millisecond lifetimes. We present HFR and MCDF calculations of the El, M1, E2 and M2 transition rates between the 3s(2)3p(3), 3s3p(4) and 3s(2)3p(2)3d levels and compare the lifetime results to most recent experimental data as well as to other predictions. [less ▲]

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See detailExperimental and theoretical studies of DyIII: radiative lifetimes and oscillator strengths of astrophysical interest
Zhang, Z. G.; Svanberg, S.; Palmeri, P. et al

in Monthly Notices of the Royal Astronomical Society (2002), 334(1), 1-10

The lifetimes of three short-lived levels belonging to the 4f(9) 6p configuration and of two long-lived levels of the 4f(9) 5d configuration of Dy iii have been measured for the first time using time ... [more ▼]

The lifetimes of three short-lived levels belonging to the 4f(9) 6p configuration and of two long-lived levels of the 4f(9) 5d configuration of Dy iii have been measured for the first time using time-resolved laser-induced fluorescence techniques. They are in good agreement with theoretical values calculated within the framework of a pseudo-relativistic configuration interaction approximation. Using the experimental lifetimes and the theoretical branching fractions, a first set of transition probabilities of astrophysical interest has been obtained for Dy III. [less ▲]

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See detailMeasurements of the ground-state ionization energy and wavelengths for the 1snp P-1(1)*-1s(2) S-1(0) (n=4-9) lines of Mg XI and FVIII
Pal'chikov, V. G.; Faenov, A. Y.; Skobelev, I. Y. et al

in Journal of Physics B-Atomic Molecular and Optical Physics (2002), 35(12), 2741-2754

The wavelengths of the 1snp P-1(1)0-1s(2) S-1(0) transitions in the He-like Mg XI (n = 4-9) and F VIII (n = 4-8) have been measured in laser-produced plasmas. The accuracy of the present measurements (0.4 ... [more ▼]

The wavelengths of the 1snp P-1(1)0-1s(2) S-1(0) transitions in the He-like Mg XI (n = 4-9) and F VIII (n = 4-8) have been measured in laser-produced plasmas. The accuracy of the present measurements (0.4-1.6 mAngstrom) is a large improvement over previous results. The Rydberg series is used to determine the ground-state ionization energy of F VIII and Mg XI: E-ion (F VIII) = 953.96 +/- 0.11 eV, E-ion (Mg XI) = 1761.88 +/- 0.15 eV. These experimental results are compared with theoretical data calculated by the 1/Z-expansion method and the HFR and MCDF approaches. Fairly good agreement between theory and experiment is observed with a precision up to 5 x 10(-5). Radiative corrections to the 1s(2) S-1(0) state are analysed and compared with experiments. It is found that QED corrections to the ground-state ionization energy are significant at the present level of experimental accuracy. [less ▲]

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See detailExperimental and theoretical investigation of radiative decay rates of metastable levels in LaII
Derkatch, A.; Ilyinsky, L.; Mannervik, S. et al

in Physical Review A (2002), 65(6),

An experimental and theoretical investigation of lifetimes of metastable levels in La II has been performed. The experimentally obtained results using the laser probing of a stored ion beam were tau=5.2 ... [more ▼]

An experimental and theoretical investigation of lifetimes of metastable levels in La II has been performed. The experimentally obtained results using the laser probing of a stored ion beam were tau=5.2+/-0.2 s for the a(1)G(4) and tau=2.1+/-0.3 s for the b(1)D(2) levels. Within the error bars, the results are in good agreement with the relativistic Hartree-Fock calculations including core polarization. [less ▲]

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See detailTime-resolved laser-induced fluorescence lifetime measurements and theoretical transition probabilities in Tb III
Biémont, Emile ULg; Garnir, Henri-Pierre ULg; Quinet, Pascal ULg et al

in Physical Review A (2002), 65(5),

Lifetimes of four short-lived levels belonging to the 4f(8)(F-7)6p configuration of Tb III have been measured using a two-step excitation time-resolved laser-induced fluorescence technique. They agree ... [more ▼]

Lifetimes of four short-lived levels belonging to the 4f(8)(F-7)6p configuration of Tb III have been measured using a two-step excitation time-resolved laser-induced fluorescence technique. They agree quite well with multiconfigurational relativistic Hartree-Fock calculations performed with inclusion of core-polarization effects. Using the experimental lifetimes and the theoretical branching fractions, a set of transition probabilities has been deduced for this ion. [less ▲]

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See detailLifetime measurements for doubly ionized uranium
Biémont, Emile ULg; Palmeri, P.; Quinet, Pascal ULg et al

in Journal of Physics B-Atomic Molecular and Optical Physics (2002), 35(7), 1701-1705

The first lifetime measurements for doubly ionized uranium are reported in the present work. They relate to five levels belonging to the configurations 5f(2)6d(2), 5f(2)6d7s and 5f(3)7p and have been ... [more ▼]

The first lifetime measurements for doubly ionized uranium are reported in the present work. They relate to five levels belonging to the configurations 5f(2)6d(2), 5f(2)6d7s and 5f(3)7p and have been obtained with a time-resolved laser-induced-fluorescence technique, the ions being produced by laser ablation of a uranium oxide target. [less ▲]

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See detailMeasurement of lifetimes by laser-induced fluorescence and determination of transition probabilities of astrophysical interest in NdIII
Zhang, Z. G.; Svanberg, S.; Palmeri, P. et al

in Astronomy and Astrophysics (2002), 385(2), 724-732

Selective lifetime measurements by time-resolved laser-induced fluorescence spectroscopy for 5 levels belonging to the 4f(3)5d configuration of doubly ionized neodymium provide a first and useful ... [more ▼]

Selective lifetime measurements by time-resolved laser-induced fluorescence spectroscopy for 5 levels belonging to the 4f(3)5d configuration of doubly ionized neodymium provide a first and useful experimental test of the relativistic Hartree-Fock calculations in this ion of astrophysical interest. As a consequence, the accuracy of the transition probabilities deduced in the present work is well assessed. These new data are expected to help astrophysicists in the future to refine the analysis of the composition of chemically peculiar stars which frequently show large overabundances of lanthanides when compared to the solar system standards. [less ▲]

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See detailDoubly ionized thorium: Laser lifetime measurements and transition probability determination of interest in cosmochronology
Biémont, Emile ULg; Palmeri, P.; Quinet, Pascal ULg et al

in Astrophysical Journal (2002), 567(2, Part 1), 1276-1283

The first lifetime measurements have been performed for six levels of doubly ionized thorium, an important cosmochronometer in astrophysics for estimating the age of the Galaxy. The levels, belonging to ... [more ▼]

The first lifetime measurements have been performed for six levels of doubly ionized thorium, an important cosmochronometer in astrophysics for estimating the age of the Galaxy. The levels, belonging to the 5f(2), 5f7p, 7s7p, and 6d7p configurations of Th III, have been measured by the time-resolved laser-induced fluorescence method and compared with relativistic Hartree-Fock calculations including configuration interaction and core-polarization effects. Taking advantage of the excellent agreement between theory and experiment, a first set of transition probabilities of astrophysical interest has been deduced for this ion from a combination of the experimental lifetimes and of the theoretical branching fractions. [less ▲]

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