Lifetimes and transition probabilities of Ar(II)

Radiative lifetimes of 16 levels belonging to the 3p⁴4p configuration of Ar(II) have been measured by using the delayed-coincidence method. Relative transition probabilities for 87 lines arising from these levels have been determined from emission line-intensity measurements. By using the corresponding experimental lifetimes, the relative transition probabilities were put on an absolute scale. Our experimental results are compared with experimental and theoretical data given by other authors and with our calculations in LS coupling.     

Line strengths and lifetimes for Kr II

Relative line strengths have been calculated for transitions between states of the 4p ⁴ 5p and 4p ⁴ 5s configurations in Kr II. The wavefunctions are obtained in intermediate coupling, including an effective correction for configuration interaction. Absolute values for the line strengths are determined using the coulomb approximation. Lifetimes for the upper 4p ⁴ 5p levels are given together with available experimental results for comparison.     

Transition probabilities of 4p−nd(n = 4, 5, 6, 7) lines of Ar(I)

Relative transition probabilities for 120 lines belonging to the 4p-nd(n = 4, 5, 6, 7) transition arrays of Ar(I) have been determined from emission-intensity measurements. Lifetime data for the 4d levels were used to obtain absolute transition probabilities. We have obtained 32 transition probabilities for 4p?4d lines. Because of the lack of data on 5p?4d transition probabilities, calculations were performed on jK coupling. Our experimental values are compared with experimental and theoretical data given by other authors.     

Transition probabilities of lines belonging to the 5p-nd (n = 4,5,6,7) transition arrays of Kr(I)

Relative transition probabilities for lines belonging to the 5p-nd (n = 4,5,6,7) transition arrays of neutral krypton have been determined by means of emission line-intensity measurements. The experimental values of the present work are compared with the experimental and theoretical data given by other authors. The relative transition probabilities for lines arising from some levels belonging to the 4p⁵nd (n = 6,7) configurations have been put on an absolute scale, taking into account experimental and theoretical data.     

Experimental lifetime of some level belonging to the 5p46d configuration of XeII

Lifetimes of eight levels belonging to the 5p⁴6d configuration of singly ionized xenon have been measured by high frequency deflection technique with a delayed coincidence single photon counting arrangement. The results have been compared with other experimental and theoretical values. The lifetimes of the 6d ²F_3/2 and 6d ⁴F_3/2 levels have been measured for the first time.     

Experimental lifetimes of some levels belonging to the 4<Emphasis Type="Italic">p</Emphasis><Superscript>4</Superscript>5<Emphasis Type="Italic">p</Emphasis> configuration of KrII using the cascade-photon-coincidence technique

Lifetimes of three levels belonging to the 4p ⁴5p configuration of singly ionized krypton have been measured using the cascade-photon-coincidence technique. The measurements have been performed under experimental condition where pressure dependent effect as well as other systematic errors are very small. The results have been compared with other experimental and theoretical values.     

Experimental lifetimes of some levels belonging to the 4p5d configuration of KrII

Lifetime of eight levels belonging to the 4p⁴5d configuration of singly ionized krypton have been measured by high-frequency deflection technique with a delayed coincidence single photon counting arrangement. The results have been compared with other experimental and theoretical values. The lifetimes of the 5d⁴P_1/2, 5d^′2D_3/2, 5d^′2F_5/2, 5d²P_3/2 and 5d²P_1/2 levels have been measured for the first time.     

4d 95p 2 configuration in the spectra of in III-Te VI

The radiative 4d ¹⁰5p-4d ⁹5p ² transitions in the spectra of the In III, Sn IV, Sb V and Te VI, ions, belonging to the silver isoelectronic sequence, have been investigated in the range 250–600 Å with high resolution. The energies of most levels of the 4d ⁹5p ² configuration with J = 1/2, 3/2, and 5/2, involved in the transitions to the 4d ¹⁰5p configuration, are found. Along the isoelectronic sequence, the 4d ⁹5p ² configuration passes from the position below the ionization limit 4d ¹⁰ in Te VI to the position above this limit in In III with corresponding autoionization effects. The autoionization widths of levels are measured. The data obtained are compared with the results of calculations by the Hartree-Fock and semiempirical methods.     

High resolution measurements of the hyperfine structure in 10 levels of Tm I

High resolution laser spectroscopy has been performed on an atomic beam of thulium. Accurate values for the magnetic dipole coupling constants of 9 excited levels belonging to the 4f¹³ 6s6p and 4f¹²5d6s² configurations and of the metastable level at 8771 cm^?1 belonging to the 4f¹³6s² ground state configuration have been obtained.     

Lifetime measurement of some excited states belonging to the 3p<Superscript>4</Superscript>nd (n=4–6) configuration of ArII

The radiative lifetimes of eight levels belonging to the 3p⁴nd (n=4–6) configuration of ArII have been measured using high frequency deflection technique together with a delayed coincidence single photon counting arrangement. Lifetimes of some of the levels have been measured for the first time. The results have been compared with other experimental and theoretical values.      

Line strengths and lifetimes for Kr II

Relative line strengths have been calculated for transitions between states of the 4p ⁴ 5p and 4p ⁴ 5s configurations in Kr II. The wavefunctions are obtained in intermediate coupling, including an effective correction for configuration interaction. Absolute values for the line strengths are determined using the coulomb approximation. Lifetimes for the upper 4p ⁴ 5p levels are given together with available experimental results for comparison.     

Radiative constants in the spectra of ions of the erbium isoelectronic sequence

The probabilities of the 4f ¹³6p→4f ¹³5d lectric dipole transitions and the lifetimes of levels of the 4f ¹³6p and 4f ¹³5d configurations are calculated for spectra of ions Yb III, Lu IV, Hf V, and Ta VI of the erbium isoelectronic sequence. The wave functions of the intermediate coupling scheme, necessary for calculating the relative line strengths, are obtained semiempirically from experimentally measured energy intervals between fine-structure levels. To pass to the absolute values, the radial integrals of transitions, evaluated with the Hartree-Fock functions, are used.     

Recent hyperfine structure investigations in the configurations 4f 136s 2, 4f 136s6p,and 4f 125d6s 2 of Tm I

By use of optical hyperfine structure investigations in the Tm I spectrum theA- values of 20 levels of the configurations 4f ¹³ 6s 6p and 4f ¹² 5d 6s ² and theA-value of 4f ¹³ 6s ^{2 2} F _5/2 were determined very accurately. These data and tenA-factors from former experiments are used for theoretical calculations. 30A-factors have been interpolated from intermediate coupling wave functions using 9 effective mono-electronic parameters. The r.m.s. deviation between experimental and theoreticalA- values amounts to 0.5 10^?3 cm^?1 and represents 3/100 of the average value of the measuredA-factors.     

A theoretical study of the npk configurations

An up-to-date picture of the known np² and np³ configurations is presented by plotting the reduced energy ? against ψ = ξ_p/(5F₂ + ξ_p) according to Edlén. It is concluded that the p² level values of S XI, Sc XVI, Ti XVII, V XVIII, Ni XV and Te III, and the p³ level values of Al VII, Si VIII, P IX, Cl X, Se II and Xe IV need to be improved. Edlén's (1972) work on n = 2 and Svensson's (1971) work on n = 3 give a very satisfactory fit to our ψ-? graphs. The (F₂ - ξ_p) V_sψ graphs enable us to study coupling variations along the same and different isoelectronic sequences.The Z-dependence of the ground intervals 4s² 4p⁴ have been studied theoretically for the first time. The level values are represented, within less than 0.2% error, by semi-empirical formulae having 3–5 adjusted parameters and are based on data obtained from laboratory observations. The results provide means for checking laboratory and astrophycial identifications and measurements.     

Tensor polarizabilities of levels of the configurations 4f 13 6s6p and 4f 12 5d6s 2 in thulium I

The level-crossing technique with parallel electric and magnetic fields was used to measure the tensor polarizabilities of six levels of the configuration 4f ¹³ 6s6p + 4f ¹² 5d6s ² in the Tm I-spectrum. Using intermediate coupling wave functions given by Camus and the experimental values of the tensor polarizabilities, the radial integrals for electric dipole transitions from levels of the configuration 4f ¹³6s6p + 4f ¹²5d6s ² to levels of the configuration 4f ¹³ 5d6s + 4f ¹² 6s ²6p have been determined. The results areI(4f ¹³6s6p,4f ¹³5d6s)=1.98(45)ea ₀ andI(4f ¹²5d6s ²,4f ¹²6s ²6p) = 0.88(25)ea ₀. A comparison between the experimental and the calculated values of the tensor polarizabilities shows an excellent agreement, provided that these radial integrals and the radial integrals for the electric dipole transitions to the ground state configuration 4f ¹³6s ² as determined by Wallenstein from lifetime measurements are used in the calculation, instead of radial integrals computed by Camus with Hartree-Fock wave functions.     

Changes in mean-square nuclear charge radii in Er from optical isotope shifts by laser-atomic-beam spectroscopy

High-resolution laser-atomic-beam spectroscopy has been applied to investigate transitions 4f ¹² 6s ²?4f ¹¹ 5d6s ² and transitions starting from metastable states of the configuration 4f ¹¹ 5d6s ² of Er I. Precise values for the transition isotope shifts and for the hyperfine constants of 10 levels belonging to the configuration 4f ¹¹ 5d6s² and 9 levels belonging to high lying even-parity levels have been determined. From the isotope shift data relative changes of mean-square nuclear charge radiiδ 〈r ²〉 for all the stable Er isotopes have been deduced: ¦168,170¦ 1, ¦166,168¦ 0.984(15), ¦164,166¦ 0.984(15), ¦162,164¦ 1.198(18), ¦166,167¦ 0.3357(50). Absoluteδ 〈r ²〉 values have been obtained by calibrating the optical data with a value from muonic x-ray spectroscopy: ¦168,170¦ 0.121 (10) fm². The odd-even staggering parameter for¹⁶⁷Er has been determined: 0.683(10). Our results are compared with experimental data from electronic x-ray spectroscopy and data from calculations with the extended liquid-drop and the droplet model.     

The probabilities of radiative transitions and lifetimes of levels in the spectra of Cu XX,La IV

The probabilities of radiative electric dipole transitions 2p ⁵3p, 2p ⁶–2p ⁵3s, and 2p ⁵3d in the spectrum of neon-like copper Cu XX and 5p ⁵6p, 5p ⁶–5p ⁵6s, 5p ⁵7s, and 5p ⁵5d in the spectrum of xenon-like lanthanum La IV are calculated. The wave functions of the intermediate coupling were found from the wellknown experimental energy levels by the least-squares method (LSM). To transfer to an absolute scale the radial integrals for the transitions calculated in the form of a length on the Hartree–Fock functions have been used. By summing the calculated probabilities of the transitions, the lifetimes of the levels of configurations 2p ⁵3s, 2p ⁵3p, and 2p ⁵3d in the spectrum of Cu XX and levels of configurations 5p ⁵6s, 5p ⁵6p, and 5p ⁵7s in the spectrum of La IV have been obtained.     

Energy Levels, Transition Probabilities, Collision Strength, and Reduced Population Calculations for High Gain Predictions in Neon-Like Krypton

We calculate the atomic structure, energy levels, oscillator strengths, transition probabilities, and collision strengths for Kr XXVII. The data refer to the 157 fine-structure levels belonging to the configurations (1s²) 2s² 2p⁶, 2s²2p⁵3l, 2s¹2p⁶3l, 2s²2p⁵4l, 2s¹2p⁶4l, 2s²2p⁵5l, and 2s¹2p⁶5l, where l?=?s, p, d, f, and the calculations are performed using the fully relativistic atomic structure program FAC. We use the obtained data to calculate the level populations and gain coefficients employing the MATLAB R2012a computer program for solving simultaneously the coupled rate equations. Finally, we determine the 157 fine-structure population levels and gain coefficients for those transitions with a positive inversion factor and plot the electron density in wide range from 10¹⁹ to 10²³.     

Fine-structure energy levels, oscillator strengths and lifetimes of chlorine-like chromium

We have done relativistic calculations for the evaluation of energy levels, oscillator strengths, transition probabilities and lifetimes for Cr VIII ion. Use has been made of configuration interaction technique by including Briet-Pauli approximation. The energies of various levels from the ground state to excited levels of 3s3p⁶, 3s²3p⁴3d, 3s²3p⁴4s, 3s²3p⁴4d of Cr VIII are given in LSJ coupling scheme after fine-tuning and are compared with the experimental results compiled in the NIST Data Base. Many new lines have been predicted which have not appeared so far in the NIST Data.     

Optische übergangswahrscheinlichkeiten der Konfigurationen 3p 5 4s–3p 5 5p des Argon I

Optical transition probabilities of the configurations 3p ⁵ 4s–3p ⁵ 5p of Argon I were determined in a wall-stabilized arc plasma and compared with the theoretical results for different types of spin-orbit-coupling. Mostly the differences in the results forLS-jl- and intermediate-coupling are small compared with the deviations of the experimental values. Therefore it may be presumed that in some cases not the assumption of an approximately valid coupling scheme is responsible for the errors of the theoretical transition probabilities, but the other quantum mechanical approximation processes.