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  • Recommended values for β+-delayed proton and α emission
    Atom. Data Nucl. Data Tables (IF 6.349) Pub Date : 2020-01-09
    J.C. Batchelder

    Beta+-delayed proton (or α) emission is a typical decay mode of very neutron-deficient nuclei. Valuable information for the ground state in the precursor, such as half-life, spin, and parity, can be obtained by studying the β+-p decay properties. The high efficiency and unique experimental signature for detecting protons allow one to study states in the β +-decay daughter that are not accessible through other means. By measuring the properties of protons emitted to a known state in the daughter, information on the structure of the proton-unbound state can be obtained. The known nuclei that exhibit this decay mode are evaluated to give the recommended values for the nuclear properties of these nuclei. This includes branching ratios, and half-lives. In addition for those nuclei with known resolved proton transitions, proton energies, intensities, and the energies of the proton-emitting states are compiled. A list of experimental references for each β +-p precursor is also given. All papers published prior to June 2019 have been considered in adopting the properties given in this work.

    更新日期:2020-01-11
  • Review of experimental photon-induced Kβ/Kα intensity ratios
    Atom. Data Nucl. Data Tables (IF 6.349) Pub Date : 2019-11-29
    S. Daoudi, A. Kahoul, N. Kup Aylikci, J.M. Sampaio, J.P. Marques, V. Aylikci, Y. Sahnoune, Y. Kasri, B. Deghfel

    In this paper, we present a compilation of the measured photon-induced Kβ/Kα intensity ratio values published in the literature from 1969 to 2018. In the considered period, we found about 1118 values (127 papers) for elements with 11≤Z≤96. The analysis of the distribution of these experimental data values in function of the atomic number shows that almost all the elements from 11Na to 96Cm are covered, except some isolated cases with no data or less than two data values were found. It has been observed that the most exploited targets are in the region 22≤Z≤30 and 39≤Z≤42 and include an important number of data values. A critical examination of these data using weighted average values (Kβ/Kα)w have been calculated for each element and recommended weighted values have been proposed.

    更新日期:2019-11-29
  • Table of electronic factors for E0 electron and electron–positron pair conversion transitions
    Atom. Data Nucl. Data Tables (IF 6.349) Pub Date : 2019-06-25
    J.T.H. Dowie, T. Kibédi, T.K. Eriksen, A.E. Stuchbery

    A new tabulation of electronic factors is reported for electron conversion for elements of Z from 5 to 126 and electronic factors for electron–positron pair conversion for elements of even Z from 4 to 100. The electronic factors for electron conversion, ΩCE(E0), were calculated using a modified version of the CATAR program developed by Pauli and Raff with a relativistic-Hartree–Fock–Slater approach (Pauli and Raff, 1975). The electronic factors for electron–positron pair conversion, ΩIPF(E0), were calculated using the model developed by Wilkinson (1969). The data tables presented here cover all atomic shells up to R2 and transition energies from 1 keV to 6000 keV and from 1100 keV to 8000 keV for pair conversion. A comparison with previous electronic factor tabulations is presented. Ratios of experimental Ω(E0) values for 83 E0 transitions in 8≤Z≤98 are compared to this tabulation. Two examples of how to use the tabulation to extract E0 strengths are also included.

    更新日期:2019-11-04
  • Energy levels and radiative rates for transitions in S-like Sc VI, V VIII, Cr IX, and Mn X
    Atom. Data Nucl. Data Tables (IF 6.349) Pub Date : 2019-06-27
    Kanti M. Aggarwal

    Energy levels, radiative rates and lifetimes are reported for four S-like ions, namely Sc VI, V VIII, Cr IX, and Mn X. Two independent atomic structure codes, namely the general-purpose relativistic atomic structure package (grasp) and the flexible atomic code (fac), have been adopted for calculating the energy levels, with differing amounts of configuration interaction. This is mainly to make some assessment of accuracy. However, the grasp alone is used for calculating the remaining parameters. Results are reported for varying number of levels of these ions, and for calculating lifetimes contributions are included from all types of transitions, i.e. E1, E2, M1, and M2. Comparisons are made with the earlier available experimental and theoretical results and assessments of accuracy are given for each ion. Additionally, the presently reported data cover a significantly larger number of levels and transitions than already available in the literature for the four S-like ions.

    更新日期:2019-11-04
  • Paschen-series spectral lines of H atoms in a strong magnetic field
    Atom. Data Nucl. Data Tables (IF 6.349) Pub Date : 2019-07-05
    F.L. Liu, L.B. Zhao

    Paschen-series spectral lines have been calculated for H atoms in the presence of strong magnetic fields. Wavelengths and transition probabilities are presented for 54 electric dipole transitions as a function of magnetic field strengths ranging from ∼ 0.001 a.u. to ∼ 1 a.u. The effect of the finite proton mass is taken into account. The present calculations involve five symmetries 0±, (−1)±, and (−2)+, and the 6 lowest electronic states for each symmetry, and thus a total of 26 magnetized atomic states are contained if excluding the 4 atomic states relevant to Lyman-series and Balmer-series spectral lines. The obtained results are compared with the available theoretical data. Our detailed atomic data, energy level differences between the initial and final states and dipole strengths under the infinite proton mass, for the selected Paschen-series spectral lines are compared to those from the other theoretical methods, and excellent agreement is shown.

    更新日期:2019-11-04
  • Energy levels, oscillator strengths, radiative transition probabilities, level lifetimes and electron-impact excitation rate coefficients for Ne-like Mo XXXIII
    Atom. Data Nucl. Data Tables (IF 6.349) Pub Date : 2019-07-30
    Cristian Iorga, Viorica Stancalie

    The energy levels, oscillator strengths, radiative decay rates, lifetimes, collision strengths, direct and resonance electron-impact excitation rate coefficients have been computed for the 257 fine-structure levels arising from 1s22s22p5nl and 1s22s2p6n′l′ configurations belonging to the Mo32+ ion with n≤7, l≤4 and n′≤5, l′≤4. The model-potential approach is used for the target ion structure calculations. Additionally, we employ the multiconfiguration Dirac–Hartree–Fock method to further assess the energy levels and transition probabilities. The collision strengths for the electron-impact direct excitation are computed within the relativistic distorted-wave approximation at 34, 135, 680, 1700, 5436, and 12,740 eV scattered electron energy values. We also perform collision calculations at 85, 175, and 450 keV electron energies using the plane-wave approximation and interpolate the reduced cross section within Fano plots, thus accounting for relativistic effects at asymptotic energies. This assures the convergence of Maxwellian integration for effective collision strengths calculation at electron temperatures up to 80 keV. The resonance contribution to the excitation rates is accounted for within the independent process isolated resonance approximation by including Na-like Mo31+ doubly excited autoionization states arising from the 1s227nln′l′ configurations with n≤7,l≤4,n′≤20,l′≤8. Contributions from high n′≥21 Rydberg states to the excitation rate coefficients are included by employing the n′−3 extrapolation law for radiative and autoionization decay rates. Radiative decay of resonances to lower autoionization states followed by autoionization cascade as well as radiative damping via core transitions are included in our model. The highest rate coefficients corresponding to ground state excitations are the 2p–3d allowed and 2p–3p electric monopole transitions, respectively. Intercombination and generally higher-order electric multipole transitions amount to lower excitation rate coefficients but are not to be neglected. Magnetic transitions are only relevant for low electron temperatures since both their direct and resonance contributions to excitation significantly decrease with increasing electron energy. Present results compare well with existing data from literature. The resonance contributions play an important role in the accuracy of rate coefficients, especially for weak forbidden transitions at low electron temperatures. These results may be useful in fusion related plasmas, astrophysics and fundamental physics.

    更新日期:2019-11-04
  • Natural widths, lifetimes, and fluorescence yields for the double K-shell hole states of atoms with 10 ≤ Z ≤ 30
    Atom. Data Nucl. Data Tables (IF 6.349) Pub Date : 2019-09-19
    Karol Kozioł, Jacek Rzadkiewicz

    The natural widths, lifetimes, and fluorescence yields for the double K-shell hole states have been calculated for atoms with 10 ≤ Z ≤ 30. The Grasp2018 package was adopted to carry out a systematic computation of the Khα1,2 and Khβ1,3 radiative transition rates and Fac was used to calculate the KK−KLL, KK−KLM, and KK−KMM non-radiative Auger transition rates. The dependence of the radiative and non-radiative rates on the existence of 3s, 3p, 3d, or 4s spectator holes is studied.

    更新日期:2019-11-04
  • Theoretical level energies and transition data for ion W28+
    Atom. Data Nucl. Data Tables (IF 6.349) Pub Date : 2019-10-31
    R. Karpuškienė, R. Kisielius

    The ab initio quasirelativistic approach was used to derive transition data for Pd-like tungsten W28+ ion. This approach was developed specifically for the calculation of spectral parameters for highly charged ions. The relativistic effects were taken into account in the Breit–Pauli approximation. The configuration interaction method was applied to include electron correlation effects. The ground configuration 4p64d10 and the lowest excited 4p64d94f were considered. The calculations for W28+ were performed with different sets of interacting configurations in order to evaluate reliability and accuracy of produced results. Level energies, radiative lifetimes τ, Landé g-factors were determined for the excited configuration 4p64d94f of W28+ levels. The radiative transition wavelengths λ and emission transition probabilities A for the electric and magnetic transitions of various multipole order (up to E5 and M4) among the levels of these two configurations were produced. The uncertainties of computed spectroscopic parameters were evaluated.

    更新日期:2019-11-04
  • Data for secondary-electron production from ion precipitation at Jupiter III: Target and projectile processes in H+, H, and H− + H2 collisions
    Atom. Data Nucl. Data Tables (IF 6.349) Pub Date : 2019-10-26
    D.R. Schultz, H. Gharibnejad, T.E. Cravens, S.J. Houston

    To extend the range of data required for modeling the secondary-electron production from ion precipitation into the upper atmosphere of Jupiter, inelastic processes for collisions of 1 keV to 25 MeV H+, H, and H− with H2 are considered. As in other work treating the dominant heavy-ion species of magnetospheric origin, O and S ions (Schultz et al., 2017, 2019; Gharibnejad et al., 2019) the classical trajectory Monte Carlo method is employed to describe the secondary-electron-producing channels (single and double ionization, transfer ionization, and single and double stripping) as well as the other inelastic channels (single and double charge transfer and projectile and target excitation) required to model the energy loss and charge state evolution of the precipitating ions in their passage through the atmospheric gas. Data is described and tabulated both as directly obtained from these calculations and normalized to widely accepted recommended values (Hunter et al., 1990) for channels for which recommendations exist. As in the previous work, the overall accuracy and completeness of the data presented is verified by use of a Monte Carlo ion-transport simulation to obtain the stopping power and ion-fraction populations as a function of impact energy in comparison with accepted values. The addition of the present data to models of secondary-electron production in Jupiter’s atmosphere improves such model’s ability to interpret in situ observations of the precipitating ions’ effect by the spacecraft Juno as well as enhancing the physical reality of models of the coupling of the Jovian magnetosphere, ionosphere, and atmosphere.

    更新日期:2019-11-04
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