References of "Biémont, Emile"
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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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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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