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.     

Lifetimes and transition probabilities in Kr V

Weighted oscillator strengths (gf), weighted transition probabilities (gA) and lifetimes are presented for all experimentally known dipole transitions and levels of Kr V. Values were determined by four methods. Three of them are based on the Hartree–Fock method, including relativistic corrections and core-polarization effects, with electrostatic parameters optimized by a least-squares procedure in order to obtain energy levels adjusted to the corresponding experimental values. The fourth method is based on a relativistic multiconfigurational Dirac–Fock approach. In addition, 47 new classified lines belonging to the Kr V spectrum are presented.     

Experimental transition probabilities of some Xe(I) lines

Using the light absorption technique in a ¹³²Xe afterglow plasma, we have measured the relative transition probabilities for several xenon lines which have the metastable 6s[$\text{3}\text{2}$]₂ or the resonant 6s[$\text{3}\text{2}$]₁ states as their lowest transition level. Because the transition probabilities of the 8819 Å (6p[$\text{5}\text{2}$]₃ ? 6s[$\text{3}\text{2}$]²) and 8280 Å (6p[$\text{1}\text{2}$]₀ ? 6s[$\text{3}\text{2}$]₁) lines are relatively well known, we have chosen these as reference lines and have thus been able to determine the absolute values of the transition probabilities for 19 xenon lines corresponding to transitions from 6p, 6p′, 7p, 8p, 9p, 4f and 5f to 6s[$\text{3}\text{2}$]₂, and for four lines corresponding to the transitions 6p?6s[$\text{3}\text{2}$]₁.     

Absolute transition probabilities in 130Xe

Lifetime measurements of the excited states of ¹³⁰Xe were carried out by delayed coincidence measurements between the β-spectrum of ^130gI and the conversion lines that de-excite the levels, using a double-lens coincidence spectrometer. The mean lifetimes of the 2362 keV and 536 keV levels were determined as τ = 13.5±2 psec and 12.0±3 psec, respectively. The sum of the mean lifetimes of the 1204 keV and 1944 keV levels was measured as 4.0±1.6 psec. Conversion coefficients were measured for the most prominent transitions. The 2362 keV state was assigned as a two-quasi-particle configuration and its de-excitation mode to the ground quasi-rotational band could be accounted for by a small amplitude admixture of the 6⁺ rotational configuration. The present B(E2; 0⁺ → 2⁺) value for the 536 keV state is in excellent agreement with a pairing plus quadrupole calculation for spherical nuclei. On the other hand, the energy spacings in this nucleus can be reproduced by the asymmetric rotational model with the parameters μ = 0.60, γ = 24°. The predicted sum of the lifetimes for the 4⁺ and 6⁺ rotational states agrees with our result within the experimental errors.     

Lifetimes,branching ratios and transition probabilities in molybdenum I

The radiative lifetimes of 14 excited levels in Mo I have been measured by time-resolved laser fluorescence spectroscopy. Emission branching ratios for the decay of these levels have been measured to determine absolute transition probabilities for 135 lines in the wavelength range 2600–6800Å. The transition probabilities are compared with earlier values. Erroneous J assignments in the literature are corrected.     

Lifetimes,branching ratios,and transition probabilities in Mo I

The radiative lifetimes of 56 levels in Mo I have been measured by the method of laser-induced fluorescence from sputtered metal vapor. Emission branching ratios have been measured for these levels to determine transition probabilities for 570 Mo I transitions in the wavelength range 2944–9767 Å. The uncertainty in the transition probability of stronger branches is typically less than 5%.     

Absolute transition probabilities of Xe(I) visible lines

Absolute transition probabilities of (5p⁵6s-6p⁵6p¹) and (5p⁵6s-5p⁵7p) xenon lines have been measured in emission in a conventional shock tube. The method of data collection and reduction enables optical depth compensation to be made in a straightforward way. Results are compared with theoretical and with other experimental data.     

Relativistic calculations of one-photon transition probabilities in hydrogen-like ions

The one-photon transition probabilities in hydrogen-like ions are calculated for nuclear charge numbers in the range 1 ≤ Z ≤ 100. The calculations are performed in the framework of the relativistic Dirac’s theory for the states with the principal quantum numbers n = 2,3, 4. The finite nuclear size effect is taken into account. The role of the quantum electrodynamics (QED) and nuclear recoil corrections is also considered.     

Comments on transition probabilities of Argon II

A comment is given on the method of determining transition-probability values in a previous paper of one of the authors. A revised table of values of some Argon II transitions is presented.     

Experimental transition probabilities and Stark broadening for singly-ionized bismuth

Absolute strengths and Stark broadening parameters of the prominent (4200–6900 Å) lines of Bi(II) have been measured in emission using a gas-driven shock tube. Thermodynamic and photometric variables were determined redundantly. Comparison of the experimental ? values (accuracies of 27–50%) with literature data on the homologous structure sequence N(II), P(II) discloses systematic behavior similar to trends reported for the C(II), Si(II), Ge(II), Sn(II), and Pb(II) sequence. Parameters for Stark-effect broadening (accuracies of 25–30%) are compared with predictions of a semi-empirical model.     

Energy Levels,Lifetimes, and Radiative Data of Xe XXIV

Journal of Applied Spectroscopy - The multi-configuration Dirac–Hartree–Fock method is employed to calculate the energy levels, wavelengths, transition probabilities, and line strengths...     

Measurement of ultraviolet Argon(II) transition probabilities

The transition probabilities of twelve Ar(II) lines around 300nm have been measured in a stationary arc experiment at 1 atm. The reported data are based on absolute intensities, calibrated by the continuum radiation of a high temperature hydrogen plasma. For two lines the maximum emission coefficient at 26500 K has been used for an immediate determination of the respective A_mn-values. These data serve for temperature measurements at lower arc currents, where the other lines are investigated. The results, the uncertainty of which should be below ±15%, agree satisfactorily with coulomb approximation calculations, but show severe discrepancies as compared with more recent NBS tables.     

Determination of transition probabilities by laser-induced breakdown spectroscopy with curve-of-growth measurements

A method for the measurement of transition probabilities using laser-induced plasmas as spectroscopic sources is presented. To check its validity, the method is applied to 19 Ni II lines, most of them with known A_ki values. The method is based on the measurement of curves of growth using samples with varying concentrations of the element of interest (here, nickel-copper alloys with nickel contents in the range 0.11-27 at%). The plasma is characterized by a reduced set of parameters, obtained by usual techniques (Boltzmann plot and Stark shift) combined with the curve-of-growth methodology. The transition probabilities are determined by fitting experimental curves of growth to calculations based on the plasma parameters. The use of curves of growth allows eliminating the systematic error due to the self-absorption in the measurement of transition probabilities, and is applicable to intense as well as very weak lines.     

Experimental transition probabilities and improved level energies in Yb III

Radiative lifetimes of nine out of the twelve 4f¹³6p levels in Yb III have been measured, seven of these for the first time. A Penning discharge lamp is introduced as a continuous plasma source, in which the lifetimes are determined with the time-resolved laser-induced fluorescence technique by pumping from metastable 5d and 6s levels. Spectra of the same source are recorded with a Fourier-transform spectrometer, which are used to derive branching fractions of the 6p and 7s levels. Combined with the lifetimes, the branching fractions are used to determine 81 experimental transition probabilities. Wavelengths of 142 Yb III transitions are measured and the uncertainties of corresponding Ritz wavenumbers are improved by an order of magnitude from the prior values. The energy of the 5d (5/2,5/2)^○ ₀ level has been shifted 144.20 cm^-1 to the higher value 45421.045 cm^-1. Much emphasis is put on data treatment and error analysis. Electronic supplementary material Supplementary Online Material     

Relativistic transition wavelenghts and probabilities for spectral lines of Ne II

Transition wavelengths and probabilities for several 2p ⁴ 3p-2p ⁴ 3s and 2p ⁴ 3d-2p ⁴ 3p lines in fluorine-like neon ion (NeII) have been calculated within the multiconfiguration Dirac-Fock (MCDF) method with quantum electrodynamics (QED) corrections. The results are compared with all existing experimental and theoretical data.     

Theoretical studies of electric quadrupole transition probabilities in Mg II

The relativistic coupled cluster theory is employed to calculate electric quadrupole (E2) transition probabilities among the doublet states of Mg II which are of interest in astrophysical problems. This is the first time a highly correlated fully ab initio method has been used to compute these quantities for this particular ion. The line strengths and transition probabilities of a number of different transitions are reported and compared with those available in the literature.Received: 4 June 2003, Published online: 30 September 2003PACS: 31.10. + z Theory of electronic structure, electronic transitions, and chemical bindingSonjoy Majumder: Present address: Institut für Theoretische Chemie, Technische Universität München, 85747 Garching, Germany.     

The theoretical calculation of transition probabilities for some excited p-d transitions in atomic nitrogen

The atomic transition probabilities are calculated for individual lines between some quartet terms of 3p↦4d and 3p↦5d transition arrays using weakest bound electron potential model theory (WBEPMT). In the determination of relevant parameters which are needed for calculation of transition probabilities, we employed numerical non-relativistic Hartree-Fock wave functions for expectation values of radius in both ground and excited states unlike to NCA method used on traditional WBEPMT procedure. We have obtained very good agreement between our results and the accepted values taken from NIST.     

Mielnik and cantoni transition probabilities

It is shown that when a Mielnik transition probability space is given, Cantoni transition probabilities can also be defined on it. A condition is given under which these transition probabilities are equal.     

Experimental transition probabilities in the Ar III and Ar IV UV spectra

We present transition probabilities (Einstein's A values) for 38 Ar III (doubly ionized argon) and 14 Ar IV (triply ionized argon) spectral lines from the wavelength interval 240–308 nm. Considered spectral lines are recorded in laboratory pulsed discharge. The relative line intensity ratio procedure has been applied in evaluation of transition probabilities. As a reference for transition probability evaluation we have chosen A value of 241.884 nm spectral line in Ar III spectrum and A value of 280.947 nm in Ar IV spectrum, both obtained theoretically. Careful analysis of experimental and existing theoretical data is conducted in order to deduce uncertainties. Presented Ar III and Ar IV A values are for the first time obtained relying on experimental data.