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Lifetime and transition probability determination in xenon ions - The cases of XeVII and XeVIII Biémont, Emile ; Clar, Mathieu ; et al in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2007), 44(1), 23-33 Radiative lifetimes have been calculated for 15 levels of Xe VII belonging to the configurations 5s5p, 5p(2), 5s5d, 5s6s, 5p5d, 4f5p, 5p5d and 5s5f and for 4 levels of the 5p and 5d configurations of Xe ... [more ▼] Radiative lifetimes have been calculated for 15 levels of Xe VII belonging to the configurations 5s5p, 5p(2), 5s5d, 5s6s, 5p5d, 4f5p, 5p5d and 5s5f and for 4 levels of the 5p and 5d configurations of Xe VIII. A relativistic Hartree-Fock approach including core-polarization effects, on the one hand, and a purely relativistic multiconfiguration Dirac-Fock method, on the other hand, have been used for the calculations. The accuracy of the present set of results has been assessed through comparisons with radiative lifetime measurements obtained by beam-foil spectroscopy. A good agreement between theory and experiment is observed for most of the levels. A new set of transition probabilities is proposed for 169 transitions of Xe VII and 45 transitions of Xe VIII. [less ▲] Detailed reference viewed: 28 (0 ULg)Radiative decay from the 7s(1/2) level in Pb+ and transition probabilities of astrophysical interest in Pb+ and Bi++ Quinet, Pascal ; Biémont, Emile ; et al in Journal of Physics B-Atomic Molecular and Optical Physics (2007), 40(10), 1705-1712 In the present work, we report on experimental and theoretical determination of the decay rates from the 7s(1)/2 state in singly ionized lead. Lifetime measurements performed using time-resolved laser ... [more ▼] In the present work, we report on experimental and theoretical determination of the decay rates from the 7s(1)/2 state in singly ionized lead. Lifetime measurements performed using time-resolved laser-induced fluorescence spectroscopy and lifetime computations carried out with themulticonfiguration Dirac-Fock method allow us to solve the discrepancies previously observed between theory and experiment for this level. New transition probabilities are proposed for the two depopulation channels, i. e. the 6p(1/2-7s1/2) and 6p(3/2-7s1/2) transitions of astrophysical interest in Pb II and Bi III, respectively. [less ▲] Detailed reference viewed: 17 (0 ULg)Wavelengths and transition probabilities in heavy Ge-like ions (70 <= Z <= 92) ; Quinet, Pascal ; Biémont, Emile et al in Atomic Data and Nuclear Data Tables (2007), 93(3), 355-374 Wavelengths and transition probabilities have been calculated for the 4s(2)4P(2) -4s4P(3) and 4s(2)4p(2) -4s(2)4p4d allowed transitions and for the forbidden (M1 and E2) transitions occurring within the ... [more ▼] Wavelengths and transition probabilities have been calculated for the 4s(2)4P(2) -4s4P(3) and 4s(2)4p(2) -4s(2)4p4d allowed transitions and for the forbidden (M1 and E2) transitions occurring within the ground configuration (4s(2)4p(2)) in the heavy Ge-like ions with Z = 70-92. The fully relativistic multiconfiguration Dirac-Fock method taking into account both the correlations within the n = 4 complex and the QED effects has been used for the calculations. The present results are compared to and agree well with recent electron-beam ion-trap measurements in tungsten, osmium, gold, bismuth, thorium, and uranium. (C) 2006 Elsevier Inc. All rights reserved. [less ▲] Detailed reference viewed: 21 (0 ULg)Transition probabilities in complex ions: The case of americium ; Quinet, Pascal ; Biémont, Emile in Journal of Electron Spectroscopy and Related Phenomena (2007), 156 We report on the first calculations of transition probabilities in neutral americium, a heavy radioactive element belonging to the actinide group. A relativistic Hartree-Fock approach, including core ... [more ▼] We report on the first calculations of transition probabilities in neutral americium, a heavy radioactive element belonging to the actinide group. A relativistic Hartree-Fock approach, including core-polarization effects, has been used for obtaining branching fractions and radiative lifetimes for some low-lying levels belonging to the 7s7p configuration. A comparison with the few experimental results available shows reasonable agreement between theory and experiment. (c) 2006 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 12 (0 ULg)Transition probabilities and lifetimes for atoms and ions from the sixth row of the periodic table and the database DESIRE ; Quinet, Pascal ; et al in Journal of Electron Spectroscopy and Related Phenomena (2007), 156 We have started a systematic investigation of the radiative properties of the elements of the sixth row of the periodic table. Using a combination of experimental radiative lifetimes obtained with the ... [more ▼] We have started a systematic investigation of the radiative properties of the elements of the sixth row of the periodic table. Using a combination of experimental radiative lifetimes obtained with the time-resolved laser-induced fluorescence (LIF) technique and of theoretical branching fractions (BF) calculated with a HFR approach taking configuration interaction and core-polarization effects into account, transition probabilities have been deduced for a number of transitions of astrophysical interest. So far results have been obtained for the elements Ta, Re, Os, Ir, Tl or An or their ions. The results obtained are stored in the database DatabasE for the SIxth Row Elements (DESIRE), an extension of the database DREAM, which will be progressively created on a web site of the University of Mons-Hainaut in Belgium. In the present paper, some emphasis is put on the procedures followed to obtain the new results but also on the difficulties associated with their determination. (c) 2006 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 22 (1 ULg)Laser-probing measurements and calculations of lifetimes of the 5d D-2(3/2) and 5d D-2(5/2) metastable levels in BaII ; Biémont, Emile ; et al in Physical Review A (2007), 75(5), 1-6 The two metastable levels 5d(2)D(3/2) and 5d(2) D-5/2 in Ba II both show extremely long lifetimes of the order of several tens of seconds each. This has been found both by experiments and by theoretical ... [more ▼] The two metastable levels 5d(2)D(3/2) and 5d(2) D-5/2 in Ba II both show extremely long lifetimes of the order of several tens of seconds each. This has been found both by experiments and by theoretical predictions. The small transition probabilities associated with these two levels make them interesting and challenging for theoreticians as well as for experimentalists. Several calculations and measurements of these two lifetimes have been made previously but discrepancies between the results are present. This article presents values of ??? = 89.4 +/- 15.6 s for the D-2(3/2) level and ??? = 32.0 +/- 4.6 s for the D-2(5/2) level measured in a beam-laser experiment performed at the ion storage ring CRYRING. These values are supported by our new calculations resulting in ???= 82.0 s for the D-2(3/2) level and ???= 31.6 s for the D-2(5/2) level. [less ▲] Detailed reference viewed: 17 (0 ULg)Wavelengths and transition probabilities for n= 4 -> n '=4 transitions in heavy Cu-like ions (70 <= Z <= 92) ; Quinet, Pascal ; Biémont, Emile et al in Atomic Data and Nuclear Data Tables (2007), 93(3), 537-547 Wavelengths and transition probabilities have been calculated for the n = 4 ->-> n' = 4 allowed transitions in the heavy Cu-like ions with Z = 70-92. Fully relativistic multiconfiguration Dirac-Fock (MCDF ... [more ▼] Wavelengths and transition probabilities have been calculated for the n = 4 ->-> n' = 4 allowed transitions in the heavy Cu-like ions with Z = 70-92. Fully relativistic multiconfiguration Dirac-Fock (MCDF) calculations were carried out. They take into account the correlations within the it = 4 complex, the core-valence n = 3 ->-> n' = 4 virtual excitations, and quantum electrodynamics effects. The present results are compared to and agree well with recent electron-beam ion-trap (EBIT) measurements in ytterbium, tungsten, osmium, gold, lead, bismuth, thorium, and uranium. (C) 2006 Elsevier Inc. All rights reserved. [less ▲] Detailed reference viewed: 18 (0 ULg)Improved atomic data for iridium atom (Ir I) and ion (Ir II) and the solar content of iridium ; ; Quinet, Pascal 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 ▲] Detailed reference viewed: 22 (2 ULg)Decay of metastable states in NdII Biémont, Emile ; ; et al in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2007), 41(2), 211-219 The difficulty associated with an accurate determination of transition rates for forbidden lines in lowly ionized heavy elements is illustrated in the case of Nd II. We have investigated the radiative ... [more ▼] The difficulty associated with an accurate determination of transition rates for forbidden lines in lowly ionized heavy elements is illustrated in the case of Nd II. We have investigated the radiative decay of the low-lying metastable levels in Nd+ including the two levels 4f(4)(I-5) 5d K-6(11/2) and 4f(4)(I-5) 5d I-6(13/2). In these two particular cases, using di. erent theoretical approaches, we. nd that the decay is dominated by the M1 channels but that the E2 contributions are of the same order of magnitude. These levels have also been studied experimentally by lifetime measurements with the heavy ion storage ring CRYRING of Stockholm University. The difficulties encountered when performing such experiments are underlined and discussed. [less ▲] Detailed reference viewed: 12 (0 ULg)Radiative parameters for some transitions arising from the 3d(9)4d and 3d(8)4s(2) electronic configurations in CuII spectrum ; ; Biémont, Emile et al in Journal of Physics B-Atomic Molecular and Optical Physics (2007), 40(1), 167-176 Transition probabilities of 41 transitions originating from the 3d(9)4d and 3d(8)4s(2) electronic configurations of singly ionized copper have been determined using laser-induced breakdown spectroscopy ... [more ▼] Transition probabilities of 41 transitions originating from the 3d(9)4d and 3d(8)4s(2) electronic configurations of singly ionized copper have been determined using laser-induced breakdown spectroscopy. The Cu II ions have been produced by laser ablation. The experimental relative transition probabilities have been converted into an absolute scale using measured branching fractions and theoretical radiative lifetimes of the corresponding upper states obtained by a relativistic Hartree-Fock method taking core-polarization and configuration interaction effects into account. Comparison of the new results with previously available data is also presented. [less ▲] Detailed reference viewed: 16 (0 ULg)Radiative decay of the 4d(5)(S-6)5p z(5,7)P(o) states in TcII: comparison along the homologous and isoelectronic sequences. Application to astrophysics ; Quinet, Pascal ; Biémont, Emile et al in Monthly Notices of the Royal Astronomical Society (2007), 374(1), 63-71 Using three independent theoretical approaches (CA, HFR+CP, AUTOSTRUCTURE), oscillator strengths have been calculated for a set of Tc II transitions of astrophysical interest and the reliability of their ... [more ▼] Using three independent theoretical approaches (CA, HFR+CP, AUTOSTRUCTURE), oscillator strengths have been calculated for a set of Tc II transitions of astrophysical interest and the reliability of their absolute scale has been assessed. The examination of the spectra emitted by some Ap stars has allowed the identification of Tc II transitions in HD 125248. This Tc II detection should however await confirmation from spectral synthesis relying on dedicated model atmospheres. New partition functions are also provided for Tc I, TcII and Tc III for temperatures ranging between 4000 and 13 000 K. [less ▲] Detailed reference viewed: 13 (0 ULg)Multiconfiguration Dirac-Fock wavelengths and transition rates in the X-ray spectra of highly charged Ga-like ions from Yb39+ to U61+ Quinet, Pascal ; Biémont, Emile ; et al in Atomic Data and Nuclear Data Tables (2007), 93(1), 167-182 A multiconfiguration Dirac-Fock (MCDF) technique has been used for computing the wavelengths and transition probabilities for lines in the X-ray spectra of the gallium-like ions from Yb XL to U LXII ... [more ▼] A multiconfiguration Dirac-Fock (MCDF) technique has been used for computing the wavelengths and transition probabilities for lines in the X-ray spectra of the gallium-like ions from Yb XL to U LXII. Results are presented for the 4s(2)4p-4s(2)4d and 4s(2)4p-4s4p(2) allowed transitions (E1) as well as for the forbidden transitions (M1 and E2) within the ground configuration 4s(2)4p. A comparison of the calculated wavelengths with the few experimental results available is also presented. (c) 2006 Elsevier Inc. All rights reserved. [less ▲] Detailed reference viewed: 12 (0 ULg)Application of Laser Induced Breakdown Spectroscopy (LIBS) to the determination of transition probabilities of laser lines in Au II spectrum ; ; Biémont, Emile et al Conference (2007) Experimental branching fractions for laser lines arising from excited states of 5d97s configuration of Au II have been determined by application of Laser Induced Breakdown Spectroscopy (LIBS). The ... [more ▼] Experimental branching fractions for laser lines arising from excited states of 5d97s configuration of Au II have been determined by application of Laser Induced Breakdown Spectroscopy (LIBS). The experimental relative transition probabilities were converted into an absolute scale using theoretical values for the radiative lifetimes of the corresponding states, calculated in this work. Transition probabilities and radiative lifetimes have been determined by a relativistic Hartree - Fock method taking configuration interaction and core-polarization effects into account. A comparison of the present results with the available theoretical values has been made and shows a reasonable agreement although discrepancies are observed between theory and experiment for some transitions. [less ▲] Detailed reference viewed: 38 (0 ULg)Inclusion of Electric Octupole Contributions Explains the Fast Radiative Decays of Two Metastable States in Ar+ ; ; et al in Physical Review Letters (2007), 99 A laser probing investigation has yielded the lifetimes of the 3s23p41D3d 2G7=2;9=2 metastable doublet states of Ar. The results, obtained with the CRYRING ion storage ring of Stockholm, are 3:0 0:4 and 2 ... [more ▼] A laser probing investigation has yielded the lifetimes of the 3s23p41D3d 2G7=2;9=2 metastable doublet states of Ar. The results, obtained with the CRYRING ion storage ring of Stockholm, are 3:0 0:4 and 2:1 0:1 s, respectively. Comparisons with theoretical values calculated with two independenttheoretical approaches, i.e., the pseudorelativistic Hartree-Fock method and the multiconfiguration Breit-Pauli approach, have allowed us to establish the unexpected and extraordinary strong contribution of an electric octupole (E3) transition to the ground state, in addition to the M1 decay channels to the 3d 2;4F states and the E2 contributions to the 4s 2P, 2D states. [less ▲] Detailed reference viewed: 15 (1 ULg)Relativistic atomic data for EUV and X-ray spectra of highly charged Cu-, Zn-, Ga- and Ge-like ions (70 ≤ Z ≤ 92) Quinet, Pascal ; Biémont, Emile ; et al in Journal of Physics : B Atomic Molecular & Optical Physics (2007), 58 Wavelengths and transition probabilities have been calculated for the n=4, Δn=0 allowed transitions in the heavy Cu-, Zn-, Ga- and Ge-like ions with Z=70–92. Fully relativistic multiconfiguration Dirac ... [more ▼] Wavelengths and transition probabilities have been calculated for the n=4, Δn=0 allowed transitions in the heavy Cu-, Zn-, Ga- and Ge-like ions with Z=70–92. Fully relativistic multiconfiguration Dirac-Fock (MCDF) computations were carried out. The present results are compared to and agree well with recent electron-beam ion-trap (EBIT) measurements in Yb, W, Os, Au, Pb, Bi, Th and U ions. [less ▲] Detailed reference viewed: 16 (0 ULg)Radiative lifetime and oscillator strength determinations in potassium ions (K V, K VI and K VII) Biémont, Emile ; Garnir, Henri-Pierre ; et al in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2006), 40(1), 91-99 Oscillator strengths have been calculated for the transitions depopulating levels of the 3s(2)3p(3), 3s3p(4) configurations of K V, of the 3s(2)3p(2), 3s3p(3) configurations of K VI and of the 3s(2)3p ... [more ▼] Oscillator strengths have been calculated for the transitions depopulating levels of the 3s(2)3p(3), 3s3p(4) configurations of K V, of the 3s(2)3p(2), 3s3p(3) configurations of K VI and of the 3s(2)3p, 3s3p(2), 3p(3) and 3s3p3d configurations of K VII. A multiconfiguration Dirac-Fock method, incorporating the relativistic two-body Breit interaction and quantum electrodynamics corrections due to self-energy and vacuum polarization, has been used for the calculations. The reliability of this approach has been tested by comparison with relativistic Hartree-Fock calculations and also with some experimental measurements performed by beam-foil spectroscopy at a beam energy of 1.7 MeV. [less ▲] Detailed reference viewed: 44 (4 ULg)Transition probabilities and lifetimes in gold (Au I and Au II) ; Quinet, Pascal ; Biémont, Emile et al in Journal of Physics B-Atomic Molecular and Optical Physics (2006), 39(17), 3587-3598 Radiative lifetimes of three odd-parity levels of neutral gold (Au I) and one odd-parity level of singly ionized gold (Au II), measured using the time-resolved laser-induced fluorescence technique, have ... [more ▼] Radiative lifetimes of three odd-parity levels of neutral gold (Au I) and one odd-parity level of singly ionized gold (Au II), measured using the time-resolved laser-induced fluorescence technique, have allowed the testing of the reliability of a relativistic Hartree-Fock model of the atomic structure taking configuration interaction and core-polarization effects into account. The importance of the inclusion of the latter effects in the calculations is emphasized. The laser-induced fluorescence lifetimes, combined with the theoretical branching fractions, have allowed us to deduce oscillator strengths for six 5d(9)6s(2)-5d(9)6s6p and 5d(10)6s-5d(9)6s6p transitions of Au I and for sixty-three 5d(9)6s-5d(9)6p, 5d(9)6p-5d(9)7s and 5d(10)-5d(9)6p UV transitions of Au II. [less ▲] Detailed reference viewed: 14 (0 ULg)Radiative lifetime measurements and semi-empirical transition probability calculations in neutral rhenium ; Quinet, Pascal ; Biémont, Emile 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 ▲] Detailed reference viewed: 7 (0 ULg)Radiative lifetimes, branching fractions and oscillator strengths in PdI and the solar palladium abundance ; ; et al in Astronomy and Astrophysics (2006), 452(1), 357-362 Transition probabilities have been derived for 20 5s-5p transitions of Pd I from a combination of radiative lifetime measurements for 6 odd-parity levels with time-resolved laser-induced fluorescence ... [more ▼] Transition probabilities have been derived for 20 5s-5p transitions of Pd I from a combination of radiative lifetime measurements for 6 odd-parity levels with time-resolved laser-induced fluorescence spectroscopy and of branching fraction determination using a hollow cathode discharge lamp. Additional oscillator strengths for 18 transitions have been determined from measured lifetimes and theoretical branching fractions obtained from configuration interaction calculations with core-polarization effects included. These new results have allowed us to refine the palladium abundance in the solar photosphere: A(Pd) = 1.66 +/- 0.04, in the usual logarithmic scale, a result in close agreement with the meteoritic value. [less ▲] Detailed reference viewed: 18 (1 ULg)Radiative lifetimes and transition probabilities of astrophysical interest in ZrII ; ; 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 ▲] Detailed reference viewed: 11 (1 ULg) |
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