Radiative-lifetime measurements and calculations of odd-parity highly excited levels in Ba i

Abstract

Natural radiative lifetime measurements have been performed for 70 odd-parity highly excited levels of neutral barium in the energy range from 308 15.512 to 417 59.93 cm −1 by a time-resolved laser-induced fluorescence technique in a laser-produced plasma. The lifetime values measured in this paper are in the range from 11.3 to 901 ns. They are compared with the published lifetimes of four levels. Two of them are in good agreement, whereas for the other two our measurements are slightly longer than the published data. The reasons for the discrepancies are discussed. Comparisons with theoretical results of the Hartree-Fock method with relativistic corrections illustrate the difficulties associated with the use of Cowan's codes for obtaining accurate branching fractions for transitions depopulating highly excited levels along the Rydberg series of heavy neutral elements. This work will be useful to extend the set of oscillator strengths available in Ba I.

Precise Computation of Energy Levels and Radiative Lifetimes in the s, p, d, and f Sequence of Hydrogen Isotope, with Natural Line Widths

“…And in past few years many elements in their atomic and ionic states were studied by this theory because of its semi-empirical nature. All these studies show remarkably good agreement in comparison with experimental results [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

“…utilizing The Radiative lifetimes 'τ', the uncertainty in energy levels due to principal of uncertainty can be computed by using expression [28]. Γ= # $% (10) In equation (10), Γ is natural line width and h is Planck's constant.…”

Radiative lifetimes, branching fractions, and oscillator strengths of some levels in Be I

“…In the measurement, all possible effects introducing systematic errors, such as collisional effects, radiation trapping, flight-out-ofview effect were minimized through appropriate variations of experimental conditions [18] . When the conditions are varied, e.g., reducing the excitation energy, adjusting the entrance slit position of the monochromator in vertical direction and the delay time between the excitation and ablation lasers, the measured values of lifetime oscillate around a constant within uncertainty indicating that influence of these systematic effects is negligibly small.…”

Lifetime measurements of odd-parity high-excitation levels of Sm ii by time-resolved laser spectroscopy

“…In this experiment, the plasma generated through laser ablation on a samarium sample with a purity of 99.99 per cent has been employed as a stable free ion source. Previously, this technique has proved very efficient and reliable for lifetime measurements (Li et al 2000; Zhang et al 2010a,b). A 5‐mJ, 532‐nm pulse, with about 8 ns duration, emitted by a Q‐switched Nd:YAG laser (Continuum Precision II) working at a 10‐Hz repetition rate, was focused on a rotary thin target plate.…”