References of "Biémont, Emile"
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See detailTransition probabilities in Te II and Te III
Zhang, W; Palmeri, P; Quinet, Pascal ULg et al

in Astronomy and Astrophysics (2013), 551

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See detailStellar laboratories : new Ge V and Ge VI oscillator strengths and their validation in the hot white dwarf RE 0503-289
Rauch, T; Werner, K; Biémont, Emile ULg et al

in Astronomy and Astrophysics (2012), 546

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See detailRadiative decay rates for W I, W II and W III allowed and forbidden transitions of interest for spectroscopic diagnostics in fusion plasmas
Quinet, Pascal ULg; Vinogradoff, V.; Palmeri, P. et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2010), 43

Transition probabilities for allowed and forbidden lines in neutral, singly ionized and doubly ionized tungsten are discussed in the present paper. For the electric dipole transitions, recommended values ... [more ▼]

Transition probabilities for allowed and forbidden lines in neutral, singly ionized and doubly ionized tungsten are discussed in the present paper. For the electric dipole transitions, recommended values are proposed from a critical evaluation of the data available in the literature. For the magnetic dipole and electric quadrupole transitions, for which no data have been published so far, a new set of radiative rates has been obtained using a relativistic Hartree–Fock approach including core-polarization effects. The tables summarizing the compiled data are expected to be useful for plasma modelling in fusion reactors. [less ▲]

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See detailTransition probabilities of astrophysican interest in the niobium ions (Nb II and Nb III)
Nilsson, H.; Hartman, H.; Engström, L. et al

in Astronomy and Astrophysics (2010)

Aims. We attempt to derive accurate transition probabilities for astrophysically interesting spectral lines of Nb ii and Nb iii and determine the niobium abundance in the Sun and metal-poor stars rich in ... [more ▼]

Aims. We attempt to derive accurate transition probabilities for astrophysically interesting spectral lines of Nb ii and Nb iii and determine the niobium abundance in the Sun and metal-poor stars rich in neutron-capture elements. Methods. We used the time-resolved laser-induced fluorescence technique to measure radiative lifetimes in Nb ii. Branching fractions were measured from spectra recorded using Fourier transform spectroscopy. The radiative lifetimes and the branching fractions were combined yielding transition probabilities. In addition, we calculated lifetimes and transition probablities in Nb ii and Nb iii using a relativistic Hartree-Fock method that includes core polarization. Abundances of the sun and five metal-poor stars were derived using synthetic spectra calculated with the MOOG code, including hyperfine broadening of the lines. Results. We present laboratory measurements of 17 radiative lifetimes in Nb ii. By combining these lifetimes with branching fractions for lines depopulating the levels, we derive the transition probabilities of 107 Nb ii lines from 4d35p configuration in the wavelength region 2240−4700 Å. For the first time, we present theoretical transition probabilities of 76 Nb III transitions with wavelengths in the range 1430−3140 Å. The derived solar photospheric niobium abundance log = 1.44 ± 0.06 is in agreement with the meteoritic value. The stellar Nb/Eu abundance ratio determined for five metal-poor stars confirms that the r-process is a dominant production method for the n-capture elements in these stars. [less ▲]

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See detailLandé g-factors along the sixth row of the periodic table
Biémont, Emile ULg; Palmeri, P.; Quinet, Pascal ULg

in Journal of Physics : B Atomic Molecular & Optical Physics (2010), 43

Land´e g-factors are calculated, in intermediate coupling, for 2084 levels belonging to atoms or ions of the sixth row of the periodic table. Extensive configuration interaction and relativistic effects ... [more ▼]

Land´e g-factors are calculated, in intermediate coupling, for 2084 levels belonging to atoms or ions of the sixth row of the periodic table. Extensive configuration interaction and relativistic effects are included in the framework of the relativistic Hartree–Fock approximation including core-polarization effects. The results have been refined using least-squares fittings of the Hamiltonian eigenvalues to the observed energy levels (when available). The new results fill in some gaps in the existing data for a large number of levels belonging to ions of astrophysical interest and are expected to be useful for investigating magnetic fields in CP stars. [less ▲]

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See detailHD 65949: Rosetta Stone or Red Herring
Cowley, C. R.; Hubrig, S.; Palmeri, P. et al

in Monthly Notices of the Royal Astronomical Society (2010), 405

HD 65949 is a late B star with exceptionally strong Hg II λ3984, but it is not a typical HgMn star. The Re II spectrum is of extraordinary strength. Abundances or upper limits are derived here for 58 ... [more ▼]

HD 65949 is a late B star with exceptionally strong Hg II λ3984, but it is not a typical HgMn star. The Re II spectrum is of extraordinary strength. Abundances or upper limits are derived here for 58 elements based on a model with Teff = 13 100K and log(g) = 4.0. Even-Z elements through nickel show minor deviations from solar abundances. Anomalies among the odd-Z elements through copper are mostly small. Beyond the iron peak, a huge scatter is found. Enormous enhancements are found for the elements rhenium through mercury (Z = 75–80). We note the presence of Th III in the spectrum. The abundance pattern of the heaviest elements resembles the N = 126 r-process peak of solar material, though not in detail. An odd-Z anomaly appears at the triplet (Zr Nb Mo), and there is a large abundance jump between Xe (Z = 54) and Ba (Z = 56). These are signatures of chemical fractionation. We find a significant correlation of the abundance excesses with second ionization potentials for elements withZ > 30. If this is not a red herring (false lead), it indicates the relevance of photospheric or near-photospheric processes. Large excesses (4–6 dex) require diffusion from deeper layers with the elements passing through a number of ionization stages. That would make the correlation with second ionization potential puzzling. We explore a model with mass accretion of exotic material followed by the more commonly accepted differentiation by diffusion. That model leads to a number of predictions which challenge future work. New observations confirm the orbital elements of Gieseking and Karimie, apart from the systemic velocity, which has increased. Likely primary and secondary masses are near 3.3 and 1.6 M , with a separation of ca. 0.25 au. New atomic structure calculations are presented in two appendices. These include partition functions for the first through third spectra of Ru, Re and Os, as well as oscillator strengths in the Re II spectrum. [less ▲]

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See detailAtomic structure calculations and Beam-foil observations of La IV
Biémont, Emile ULg; Clar, M.; Enzonga Yoca, S. et al

in Canadian Journal of Physics (2009), 87

Relativistic Hartree–Fock and multiconfigurational Dirac–Fock calculations of atomic structure and transition rates have been carried out in trebly ionized lanthanum (La3+, Z = 57). The calculations have ... [more ▼]

Relativistic Hartree–Fock and multiconfigurational Dirac–Fock calculations of atomic structure and transition rates have been carried out in trebly ionized lanthanum (La3+, Z = 57). The calculations have to cope with configuration interaction effects but also with the very complex situation of the collapse of the 4f wave function. The calculations are compared to experimental data obtained with beam-foil spectroscopy in the extreme ultraviolet, at ion energies that favour <br />the production of the spectrum La IV. Besides lines known from sliding spark discharges, many more lines are observed that have not yet been identified. Time-resolved measurements yield three level lifetimes in La IV that agree roughly with the results of our own calculations. [less ▲]

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See detailLifetime and transition probability determinationin Xe IX
Garnir, Henri-Pierre ULg; Enzonga Yoca, S.; Quinet, Pascal ULg et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2009), 110

A new set of transition probabilities is proposed for Xe IX.They have been calculated by two different theoretical approaches i.e. a fully relativistic multiconfiguration Dirac–Fock (MCDF) method and a ... [more ▼]

A new set of transition probabilities is proposed for Xe IX.They have been calculated by two different theoretical approaches i.e. a fully relativistic multiconfiguration Dirac–Fock (MCDF) method and a partly relativistic Hartree–Fock (HFR) approach takingcore-polarization effects in to account. Their accuracy has been evaluated through comparisons with lifetimeme asurements for 11 levels performed using beams of Xeþ ions produced by a 2 MVV an de Graaff accelerator. The agreement theory-experimentis nice for most of the levels and gives more weight to the theoretical models used for the calculations and, consequently,to the new transition probabilities [less ▲]

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See detailRadiative decay data for highly excited Zr I levels
Malcheva, G.; Mayo, R.; Ortiz, M. et al

in Monthly Notices of the Royal Astronomical Society (2009), 395

Radiative lifetimes of 17 excited levels in Zr I, in the energy interval 29 000–40 974 cm−1, have been investigated using the time-resolved laser-induced fluorescence method. The levels belong to the ... [more ▼]

Radiative lifetimes of 17 excited levels in Zr I, in the energy interval 29 000–40 974 cm−1, have been investigated using the time-resolved laser-induced fluorescence method. The levels belong to the 4d25s5p, 4d35p and 4d5s25p electronic configurations and were excited in a single-step process from either the ground term, 4d25s2 a 3F, or from the low-lying 4d25s2 a 3P and a 5F terms. For three levels, we confirm previous measurements while for 14 of the levels the lifetimes have been measured for the first time. The experimental results are compared to theoretical calculations performed with a multiconfiguration relativistic Hartree–Fock method including core-polarization effects. Theoretical transition probabilities of astrophysical interest, scaled by the experimental lifetimes, for the depopulating channels of the investigated levels are also presented. [less ▲]

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See detailBranching fractions and A values in singly ionized tantalum (Ta II)
Quinet, Pascal ULg; Fivet, V.; Palmeri, P. et al

in Astronomy and Astrophysics (2009), 493

Aims. We report on the theoretical and experimental lifetimes of Ta II, and calculated branching fractions for selected transitions. Methods. The theoretical data are obtained by means of a relativistic ... [more ▼]

Aims. We report on the theoretical and experimental lifetimes of Ta II, and calculated branching fractions for selected transitions. Methods. The theoretical data are obtained by means of a relativistic Hartree-Fock method with detailed attention to correlation effects. The experimental lifetimes are measured with the time-resolved, laser-induced, fluorescence technique. Results. The calculated results are in good agreement with both previously known and new experimental lifetimes. New transition probabilities have been deduced for a set of Ta II transitions of astrophysical interest. [less ▲]

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See detailRadiative lifetimes along even-parity J = 1, 2 Rydberg series of neutral tin
Zhang, W.; You, S.; Sun, C. et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2009), 55

Using the time-resolved laser-induced fluorescence (LIF) technique in a tin atomic beam, 40 natural radiative lifetimes have been measured for the even-parity J = 1 5pnp (n = 10–13, 15–19) and J = 2 5pnp ... [more ▼]

Using the time-resolved laser-induced fluorescence (LIF) technique in a tin atomic beam, 40 natural radiative lifetimes have been measured for the even-parity J = 1 5pnp (n = 10–13, 15–19) and J = 2 5pnp (n = 10–13, 15–19, 27, 31, 32), 5pnf (n = 4, 5, 9–19, 22, 23) levels along the Rydberg series and for all the 5p8p perturbing levels of neutral tin with energies in the range 52263.8 to 59099.9 cm−1. A two-step laser excitation scheme was used in the experiment. A multiconfigurational relativistic Hartree-Fock (HFR) calculation taking core-polarization effects into account has also been performed for the even-parity states for testing the ability of this approach to correctly predict the radiative properties of tin atom. Through an analysis of the energy levels structure by the multichannel quantum defect theory (MQDT), the channel admixture coefficients have been obtained and used to fit the theoretical lifetimes to the experimental ones in order to predict new values for the levels not measured. A generally good overall agreement between experimental and theoretical MQDT and HFR lifetimes has been achieved except for a few levels. [less ▲]

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See detailLand´e factors for even-parity 5pnp and 5pnf J = 1, 2 levels along the Rydberg series of Sn I
Xu, J.; You, S.; Zhang, Y. et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2009), 42

Land´e g-factors have been measured by time-resolved laser-induced fluorescence and Zeeman quantum-beat techniques for the even-parity levels of the J = 1 5pnp (n = 11–13, 15–19) and J = 2 5pnp (n = 11–13 ... [more ▼]

Land´e g-factors have been measured by time-resolved laser-induced fluorescence and Zeeman quantum-beat techniques for the even-parity levels of the J = 1 5pnp (n = 11–13, 15–19) and J = 2 5pnp (n = 11–13, 15–19, 31, 32), 5pnf (n = 4, 5, 9–19, 22, 23) Rydberg series and for all the 5p7p and 5p8p perturbing levels of neutral tin. A two-colour two-step excitation scheme was used in the experiment. The experimental results have been compared with theoretical g-values obtained by the multichannel quantum defect theory and the relativistic Hartree–Fock theory, respectively. In most cases, the theoretical values agree well with the experimental data. [less ▲]

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See detailExperimental and theoretical radiative decay rates for highly excited ruthenium atomic levels and the solar abundance of ruthenium
Fivet, V.; Quinet, Pascal ULg; Palmeri, P. et al

in Monthly Notices of the Royal Astronomical Society (2009), 396

The solar photospheric abundance of ruthenium is revised on the basis of a new set of oscillator strengths derived for Ru I transitions with wavelengths in the spectral range 2250–4710 Å. The new ... [more ▼]

The solar photospheric abundance of ruthenium is revised on the basis of a new set of oscillator strengths derived for Ru I transitions with wavelengths in the spectral range 2250–4710 Å. The new abundance value (in the usual logarithmic scale where the solar hydrogen abundance is equal to 12.00), ARu = 1.72 ± 0.10, is in agreement with the most recent meteoritic result, ARu = 1.76 ± 0.03. The accuracy of the transition probabilities, obtained using a relativistic Hartree–Fock model including core-polarization effects, has been assessed by comparing the theoretical lifetimes with previous experimental results. A comparison is also made with new measurements performed in this work by the time-resolved laser-induced fluorescence spectroscopy for 10 highly excited odd-parity levels of Ru I [less ▲]

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See detailLifetime measurements in Ru II and calculated oscillator strengths in Ru II and Ru III
Palmeri, P.; Quinet, Pascal ULg; Fivet, V. et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2009), 42

A new set of theoretical f -values is reported for 178 Ru II transitions of astrophysical interest, involving energy levels below 58 000 cm−1. The theoretical model, including core-polarization effects ... [more ▼]

A new set of theoretical f -values is reported for 178 Ru II transitions of astrophysical interest, involving energy levels below 58 000 cm−1. The theoretical model, including core-polarization effects, has been tested by comparing theoretical lifetimes with new measurements performed by time-resolved laser-induced fluorescence spectroscopy for 23 4d6(5D)5p odd levels of Ru II and by comparing theoretical and experimental Land´e g-factors. The first set of transition probabilities is proposed for 25 strong lines depopulating the 4d55p 5,7P◦ terms of Ru III. The new results will allow quantitative investigations of stellar spectra and allow the astrophysicists to refine the ruthenium abundance in stars. [less ▲]

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See detailRadiative lifetimes and transition probabilities in Hf I and Hf III
Malcheva, G.; Enzonga Yoca, S.; Mayo, R. et al

in Monthly Notices of the Royal Astronomical Society (2009), 396

Radiative lifetimes of nine odd levels in Hf III (5d6p z3P0,1, z1D2, z3D1,2,3, z3F2,3,4) and of two odd levels in Hf I (5d6s26p z3D2,3) have been determined using Time-Resolved Laser-Induced Fluorescence ... [more ▼]

Radiative lifetimes of nine odd levels in Hf III (5d6p z3P0,1, z1D2, z3D1,2,3, z3F2,3,4) and of two odd levels in Hf I (5d6s26p z3D2,3) have been determined using Time-Resolved Laser-Induced Fluorescence. The investigated levels in Hf I were excited in a single-step process from the ground term (5d26s2 a3F), whereas in Hf III we started from either the ground term 5d2 a3F or the low-lying 5d6s a3D term. For all of the investigated levels, the lifetimes have been measured for the first time. A multiconfiguration relativistic Hartree–Fock method, including core-polarization effects, has been used to compute radiative lifetimes of 15 Hf III levels, including those measured in this work. Transition probabilities for 55 transitions in Hf III are also given. [less ▲]

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See detailRadiative data in the Zr I spectrum obtained by Laser Induced Fluorescence
Malcheva, G.; Mayo, R.; Ortiz, M. et al

Conference (2008)

Radiative lifetimes of 17 excited states in Zr I, in the energy interval 29000 – 40974 cm-1, have been investigated using the Time-Resolved Laser-Induced Fluorescence (TR-LIF) method. The levels belong to ... [more ▼]

Radiative lifetimes of 17 excited states in Zr I, in the energy interval 29000 – 40974 cm-1, have been investigated using the Time-Resolved Laser-Induced Fluorescence (TR-LIF) method. The levels belong to the 4d25s5p, 4d35p and 4d5s25p electronic configurations were excited in a single - step process from levels belonging to the ground 4p25s2 a 3F or to low-lying 4p25s2 a 3P, a 5F terms. For 14 levels, the lifetimes have been measured for the first time. Experimental results are compared with theoretical calculations performed with a multiconfigurational relativistic Hartree–Fock method including core polarization effects. [less ▲]

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See detailLifetime measurements and calculated transition probabilities in WIII
Palmeri, P.; Quinet, Pascal ULg; Fivet, V. et al

in Physica Scripta (2008), 78

New experimental lifetimes for two levels in doubly ionized tungsten, W III, have been obtained using the time-resolved laser-induced-fluorescence technique. Theoretical oscillator strengths obtained from ... [more ▼]

New experimental lifetimes for two levels in doubly ionized tungsten, W III, have been obtained using the time-resolved laser-induced-fluorescence technique. Theoretical oscillator strengths obtained from a HFR calculation including the effects of core-polarization are reported for all transitions from levels below E < 70 000 cm−1 and with log g f > −2, thus greatly extending our knowledge of the radiative data in W III. Good agreement is found between the calculated lifetimes and the experimental values from this and previous works. These new results fill a gap in the available data for this ion which is expected to play an important role in fusion reactors. [less ▲]

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See detailLifetime measurements and transition probability calculations in singly ionized tungsten (WII)
Nilsson, H.; Engström, L.; Lundberg, H. et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2008), 49

New measurements of radiative lifetimes for 9 levels in singly ionized tungsten (Wii) have been performed with the time-resolved laser-induced-fluorescence technique. Transition probabilities have been ... [more ▼]

New measurements of radiative lifetimes for 9 levels in singly ionized tungsten (Wii) have been performed with the time-resolved laser-induced-fluorescence technique. Transition probabilities have been obtained from a combination of experimental lifetimes and theoretical branching fractions. The reliability of the present results is assessed through the good agreement observed between the calculated lifetimes and the experimental values from this work and from previous publications. These new results fill in a gap in the available data for this atomic species particularly important for fusion reactors. [less ▲]

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See detailLifetimes of metastable levels of singly ionized titanium: theory and experiment
Palmeri, P.; Quinet, Pascal ULg; Biémont, Emile ULg et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2008), 41

This paper presents new theoretical lifetimes of metastable levels in singly ionized titanium, Ti II. Along with the lifetimes, transition probabilities for several decay channels from these metastable ... [more ▼]

This paper presents new theoretical lifetimes of metastable levels in singly ionized titanium, Ti II. Along with the lifetimes, transition probabilities for several decay channels from these metastable levels are presented. The calculations are supported by experimental lifetime determinations of the 3d3 b 2D5/2 and 3d2(3P)4s b 2P3/2 levels along with revised values of the previously published lifetimes of the 3d2(3P)4s b 4P5/2 and 3d2(3P)4s b 2P1/2 levels originating partly from a reanalysis utilizing a recently developed method applied on the previously recorded data and partly from new measurements. The presented theoretical investigation of lifetimes of metastable levels in Ti II shows that the HFR calculations are in general compatible with measurements performed using the ion storage ring CRYRING of Stockholm University. The transition probabilities of forbidden lines derived from the new lifetime values will be useful for the diagnostics of low density laboratory or astrophysical plasmas, particularly those encountered in the strontium filament found in the ejecta of η Carinae. [less ▲]

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