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Lifetime and transition probability determinationin Xe IX Garnir, Henri-Pierre ; ; Quinet, Pascal 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 ▲] Detailed reference viewed: 29 (1 ULg)Radiative decay data for highly excited Zr I levels ; ; 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 ▲] Detailed reference viewed: 14 (1 ULg)Branching fractions and A values in singly ionized tantalum (Ta II) Quinet, Pascal ; ; 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 ▲] Detailed reference viewed: 31 (0 ULg)Radiative lifetimes along even-parity J = 1, 2 Rydberg series of neutral tin ; ; 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 ▲] Detailed reference viewed: 20 (1 ULg)Land´e factors for even-parity 5pnp and 5pnf J = 1, 2 levels along the Rydberg series of Sn I ; ; 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 ▲] Detailed reference viewed: 19 (0 ULg)Experimental and theoretical radiative decay rates for highly excited ruthenium atomic levels and the solar abundance of ruthenium ; Quinet, Pascal ; 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 ▲] Detailed reference viewed: 12 (0 ULg)Lifetime measurements in Ru II and calculated oscillator strengths in Ru II and Ru III ; Quinet, Pascal ; 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 ▲] Detailed reference viewed: 13 (1 ULg)Radiative lifetimes and transition probabilities in Hf I and Hf III ; ; 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 ▲] Detailed reference viewed: 22 (1 ULg)Spectroscopie moléculaire. Structures moléculaires et analyse spectrale Biémont, Emile Book (2008) Detailed reference viewed: 68 (4 ULg)Radiative data in the Zr I spectrum obtained by Laser Induced Fluorescence ; ; 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 ▲] Detailed reference viewed: 17 (2 ULg)Lifetime measurements and calculated transition probabilities in WIII ; Quinet, Pascal ; 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 ▲] Detailed reference viewed: 15 (0 ULg)Lifetime measurements and transition probability calculations in singly ionized tungsten (WII) ; ; 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 ▲] Detailed reference viewed: 18 (0 ULg)Lifetimes of metastable levels of singly ionized titanium: theory and experiment ; Quinet, Pascal ; Biémont, Emile 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 ▲] Detailed reference viewed: 17 (0 ULg)Radiative lifetime measurements and calculations in doubly ionized tantalum (Ta III) ; Biémont, Emile ; et al in Journal of Physics : B Atomic Molecular & Optical Physics (2008), 41 Radiative lifetimes of six odd-parity levels belonging to the 5d26p configuration of doubly ionized tantalum (Ta III) have been measured using the time-resolved-laser-inducedfluorescence technique ... [more ▼] Radiative lifetimes of six odd-parity levels belonging to the 5d26p configuration of doubly ionized tantalum (Ta III) have been measured using the time-resolved-laser-inducedfluorescence technique. Supporting theoretical calculations, including core-polarization effects, have been performed to model configuration interaction and to estimate branching fractions. The excellent agreement between the theoretical and experimental lifetimes allows us to assess the reliability of the 206 calculated transition probabilities. It is expected that this new set of results will be useful to astrophysicists for the investigation of the chemical composition of stars. [less ▲] Detailed reference viewed: 31 (1 ULg)Lifetime and Landé factor measurements of 5p7p levels of Sn I by time-resolved laser spectroscopy ; ; et al in Physical Review. A (2008), 78 Lifetimes for nine levels and Landé gJ factors for eight levels of the 5p7p configuration of neutral tin have been measured by the time-resolved fluorescence method and by the Zeeman quantum beat ... [more ▼] Lifetimes for nine levels and Landé gJ factors for eight levels of the 5p7p configuration of neutral tin have been measured by the time-resolved fluorescence method and by the Zeeman quantum beat technique, respectively. A two-step laser excitation technique has been used for the measurements. The results obtained are compared with relativistic Hartree-Fock lifetime and gJ values taking core-polarization effects into account. [less ▲] Detailed reference viewed: 55 (0 ULg)Laser-induced-fluorescence lifetime measurements and relativistic Hartree-Fock oscillator strength calculations in singly ionized platinum Quinet, Pascal ; ; et al in Physical Review. A (2008), 77 Radiative lifetimes of eight odd-parity states of Pt II, in the energy range from 51 408 to 64 388 cm−1, have been measured by means of the time-resolved laser-induced-fluorescence technique. Free, singly ... [more ▼] Radiative lifetimes of eight odd-parity states of Pt II, in the energy range from 51 408 to 64 388 cm−1, have been measured by means of the time-resolved laser-induced-fluorescence technique. Free, singly ionized platinum ions were obtained in a laser-produced plasma and a tunable laser with 1.5 ns duration pulse was used to selectively excite the Pt+ ions. The comparison of the experimental results with relativistic Hartree-Fock calculations emphasizes the importance of valence-valence correlation and of core-polarization effects in this complex ion. A new and extensive set of calculated oscillator strengths and transition probabilities is reported in the present paper. [less ▲] Detailed reference viewed: 44 (1 ULg)Transition probabilities in Au III ; Biémont, Emile ; et al in Physica Scripta (2008), 78 Theoretical transition probabilities are reported for doubly ionized gold (Au III). They have been obtained through the use of two different independent theoretical approaches, i.e. the SUPERSTRUCTURE ... [more ▼] Theoretical transition probabilities are reported for doubly ionized gold (Au III). They have been obtained through the use of two different independent theoretical approaches, i.e. the SUPERSTRUCTURE code and a HFR model including valence–valence and core–valence configuration interaction in a detailed way. The new scale of A-values is assessed through the comparison of the two sets of results and also through the use of a model similar to the one selected for an isoelectronic ion, i.e. Pt II, for which accurate laser-induced-fluorescence lifetimes have been measured recently. [less ▲] Detailed reference viewed: 22 (0 ULg)ATOMIC STRUCTURES OF HEAVY ELEMENTS : RECENT PROGRESS AND PERSPECTIVES Biémont, Emile ; ; et al Conference (2008) In the present paper, we discuss some recent advances concerning the determination of new radiative parameters (transition probabilities, oscillator strengths, radiative lifetimes, branching fractions ... [more ▼] In the present paper, we discuss some recent advances concerning the determination of new radiative parameters (transition probabilities, oscillator strengths, radiative lifetimes, branching fractions, Landé factors) in heavy ions. We also emphasize the difficulties that are frequently met in the field and that sometimes prevent obtaining accurate atomic data for the transitions of astrophysical interest. We concentrate particularly on the determination of radiative parameters for selected rare-earth (RE) ions (lanthanides and actinides) and for some atoms and ions of the sixth row of the periodic table. [less ▲] Detailed reference viewed: 13 (2 ULg)Experimental and theoretical transition probabilities in singly ionized gold Biémont, Emile ; ; et al in Monthly Notices of the Royal Astronomical Society (2007), 380(4), 1581-1588 Absolute transition probabilities have been measured for lines originating from the 5d(9)6d and 5d(9)7s electronic configurations in the spectrum of singly ionized gold (Au II). The laser-induced ... [more ▼] Absolute transition probabilities have been measured for lines originating from the 5d(9)6d and 5d(9)7s electronic configurations in the spectrum of singly ionized gold (Au II). The laser-induced breakdown spectroscopy has been applied to free gold atoms and ions produced by laser ablation. Absolute transition probabilities have been determined using the branching fraction and the Boltzmann plot methods. Theoretical branching fractions as well as radiative lifetime values have also been obtained by a relativistic Hartree-Fock method taking core polarization and configuration interaction effects into account. The new results are compared with previous results when available. [less ▲] Detailed reference viewed: 16 (0 ULg)Atomic data for radioactive elements RaI, RaII, AcI and AcII and application to their detection in HD 101065 and HR 465 Quinet, Pascal ; ; et al in Astronomy and Astrophysics (2007), 474(1), 307-314 Radiative data for transitions of astrophysical interest in radioactive elements Ra I, Ra II, Ac I and Ac II have been computed using a semi- empirical relativistic Hartree- Fock approach including core ... [more ▼] Radiative data for transitions of astrophysical interest in radioactive elements Ra I, Ra II, Ac I and Ac II have been computed using a semi- empirical relativistic Hartree- Fock approach including core polarization effects. Most of the oscillator strengths reported in the present paper are new. A possible detection of radium ( Ra II) and actinium ( Ac II) in the spectrum of the stars HD 101065 and HR 465 is examined and discussed. [less ▲] Detailed reference viewed: 20 (0 ULg) |
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