Time-resolved laser-induced fluorescence lifetime measurements and theoretical transition probabilities in Tb III

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 ▲]

Measurement of lifetimes by laser-induced fluorescence and determination of transition probabilities of astrophysical interest in NdIII

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 ▲]

Radiative lifetime measurements and oscillator strengths of astrophysical interest in HoIII

in Astronomy and Astrophysics (2002), 384(1), 364-370

Radiative lifetimes of three long-lived levels belonging to the 4f(10)5d configuration of Ho III have been measured, for the first time, using the time-resolved laser-induced fluorescence technique. A ... [more ▼]

Radiative lifetimes of three long-lived levels belonging to the 4f(10)5d configuration of Ho III have been measured, for the first time, using the time-resolved laser-induced fluorescence technique. A good agreement between the experimental lifetimes and theoretical results obtained within a multiconfigurational pseudo-relativistic Hartree-Fock (HFR) approach including core-polarization (CP) effects is observed provided an adequate scaling factor is applied to the <4f|r|5d> transition matrix element. From the comparison theory-experiment, it has been possible to assess the reliability of the oscillator strengths of the 4f-5d transitions of astrophysical interest, particularly for the lines depopulating the levels considered in the present work. The present results fill in a gap concerning the f-values of doubly ionized holmium and are needed for a quantitative evaluation of the holmium abundance in some peculiar stars. [less ▲]

Hyperfine structure of neutral vanadium lines and livels

in Physica Scripta (2002), 66

We have recorded hollow-cathode spectra of neutral vanadium by Fourier transform spectroscopy in the near infrared - visible region (9000-17 000 cm-1). 36 transitions showing hyperfine structure have been ... [more ▼]

We have recorded hollow-cathode spectra of neutral vanadium by Fourier transform spectroscopy in the near infrared - visible region (9000-17 000 cm-1). 36 transitions showing hyperfine structure have been analyzed, allowing us to deduce magnetic dipole constants for 27 levels belonging to the 3d44p and 3d34s4p configurations. For 22 of these levels no data were previously available. [less ▲]

Time-resolved laser spectroscopy of multiply ionized atoms: Natural radiative lifetimes in CeIV

in Physical Review Letters (2001), 87(27),

Radiative lifetimes have been measured for two excited levels of Ce IV using the time-resolved laser-induced fluorescence technique. Ce3+ ions were produced in a laser-induced plasma. In the measurements ... [more ▼]

Radiative lifetimes have been measured for two excited levels of Ce IV using the time-resolved laser-induced fluorescence technique. Ce3+ ions were produced in a laser-induced plasma. In the measurements, a suitable magnetic field was applied to reduce the recombination between electrons and the ions and thus the background light from the recombination, and special care was exercised to avoid flight-out-of-view effects on the lifetime measurements for the high-velocity ions. The experimental lifetime results, tau = 30(2) ns for the level 49 737 cm(-1) and tau = 30(3) ns for the level 52 226 cm(-1), were compared with relativistic Hartree-Fock calculations (tau = 30.5 and 30.0 ns) indicating a particularly excellent agreement. [less ▲]

Extended analysis of the spectrum of triply-ionozed Ytterbium (Yb IV) and transition probabilities

in Physica Scripta (2001), 63

Radiative lifetime measurements and transition probabilities of astrophysical interest in Er III

in Monthly Notices of the Royal Astronomical Society (2001), 321

Radiative lifetimes of seven excited states of Er III have been measured using time-resolved laser-induced fluorescence following two-photon excitation. Relativistic Hartree-Fock calculations taking core ... [more ▼]

Radiative lifetimes of seven excited states of Er III have been measured using time-resolved laser-induced fluorescence following two-photon excitation. Relativistic Hartree-Fock calculations taking core-polarization effects into account are found to be in excellent agreement with the experimental results. A large set of new calculated transition probabilities is presented for many transitions of astrophysical interest. These results will be useful for investigating the composition of chemically peculiar stars. [less ▲]

Experimental and Theoretical Energy Levels, Transition probabilities and Radiative Lifetimes in Yb III

in Journal of Physics : B Atomic Molecular & Optical Physics (2001), 34

Experimental M1 Transition Rates in Highly Charged Krypton Ions

in Physical Review. A (2001), 64

Experimental and theoretical lifetimes in Yb III

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2001), 15