Regular ArticleAtomic Data and Spectral Line Intensities for C-like Ca XV
Abstract
Electron impact collision strengths and spontaneous radiative decay rates are calculated for the C-like ion, Ca XV. The data pertain to the 46 levels of the configurations 2s22p2, 2s2p3, 2p4, 2s22p3s, 2s22p3p, and 2s22p3d. Collision strengths are calculated at three incident electron energies: 45.0, 90.0 and 135.0 Ryd. Spectral line intensities are calculated for all transitions with intensities within two orders of magnitude of the most intense Ca XV line. These are obtained by computing the excitation rate coefficients (cm3 s−1), that is, the collision strengths integrated over a Maxwellian electron distnbution, and then solving the equations of detailed balance for the populations of the 46 energy levels, assuming a collisional excitation model and an electron temperature of 4 × 106 K. This temperature is typical for Ca XV in solar and some other astrophysical plasmas. Using the excitation rate coefficients and the radiative decay rates, level populations are computed for several electron densities and are also given in this paper.
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Atomic data and spectral line intensities for Ni XVI
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Atomic data and spectral line intensities for Ni XIII
1998, Atomic Data and Nuclear Data TablesElectron impact collision strengths and spontaneous radiative decay rates are calculated for Ni XIII. The data pertain to the 48 levels of the configurations 3s23p4, 3s3p5, 3s23p33d, and 3p6. Collision strengths are calculated at five incident electron energies: 10.0, 20.0, 30.0, 40.0, and 50.0 Ry. Relative spectral line intensities are calculated for all astrophysically important transitions. These are obtained by computing the excitation rate coefficients (cm3s−1), i.e., the collision strengths integrated over a Maxwellian electron distribution, and then solving the equations of detailed balance for the populations of the 48 energy levels, assuming a collisional excitation model and an electron temperature of 2.0 × 106K. This temperature is typical for Ni XIII when formed in equilibrium by collisional ionization and recombination. Using the excitation rate coefficients and the radiative decay rates, level populations are computed for several electron densities and are given in this paper. We also investigate the effects of proton excitation and solar radiative excitation on the level populations and line intensities.
Relativistic distorted-wave collision strengths and oscillator srengths for all possible n = 2-n = 3 transition in C-like ions
1997, Atomic Data and Nuclear Data TablesRelativistic distorted-wave collision strengths have been calculated for the over 4000n= 2–n= 3 transitions in the 46 C-like ions with nuclear charge numberZin the range 9 ≤Z≤ 54, but in the interest of brevity the results are given here for only the three valuesZ= 12, 26, and 54. The calculations were made for the six final, or scattered, electron energiesE′ = 0.008, 0.04, 0.12, 0.28, 0.60, and 1.20, whereE′ is in units ofZeff2rydbergs withZeff= Z− 4.17. In addition, the transition energies and electric dipole oscillator strengths are given. To our knowledge the present work is the first publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged C-like ions to then= 3 levels.
Atomic data and spectral line intensities for Fe XI
1996, Atomic Data and Nuclear Data TablesElectron impact collision strengths and spontaneous radiative decay rates are calculated for Fe XI. The data pertain to the 48 levels of the configurations 3s23p4, 3s3p5, 3s23p33d, and 3p6. Collision strengths are calculated at three incident electron energies, 8.0, 16.0, and 24.0 Ry. Relative spectral line intensities are calculated for all astrophysically important transitions. These are obtained by computing the excitation rate coefficients, i.e., the collision strengths integrated over a Maxwellian electron distribution, and then solving the equations of detailed balance for the populations of the 48 energy levels, assuming a collisional excitation model and an electron temperature of 1.3 × 106K. This temperature is typical for Fe XI when formed in equilibrium by collisional ionization and recombination. Using the excitation rate coefficients and the radiative decay rates, level populations are computed for several electron densities and are given in this paper. We also investigate the effects of proton excitation and solar radiative excitation on the level populations and line intensities. Finally, the calculated relative line intensities are compared with experimental solar intensities where available.
Relativistic distorted-wave collision strengths and oscillator strengths for the Δn = 0 transitions with n = 2 in C-like ions with 9 ≤ z ≤ 54
1996, Atomic Data and Nuclear Data TablesRelativistic distorted-wave collision strengths have been calculated for the Δn= 0 transitions withn= 2 in C-like ions with nuclear charge numberZin the range 9 ≤Z≤ 54. The calculations were made for the six final, or scattered, electron energiesE′ = 0.03, 0.08, 0.20, 0.42, 0.80, and 1.40, whereE′ is in units ofZ2effRydbergs withZeff= Z− 4.17. In addition, the transition energies and electric dipole oscillator strengths are given. To our knowledge the present work is the first publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged C-like ions.
Electron impact excitation of carbon-like ions: An assessment of the available theoretical data
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