Atomic data and spectral line intensities for the beryllium isoelectronic sequence (Ar XV through Kr XXXIII)

Oscillator strengths, radiative decay rates, and electron collision strengths are calculated for the ions Ar XV, Ti XIX, Ni XXV, Ge XXIX, and Kr XXXIII in the Be I isoelectronic sequence. The corresponding atomic data for the ions Ca XVII, Cr XXI, Fe XXIII, Zn XXVII, and Se XXXI are determined by interpolation. The configurations included in the calculation of the atomic data are 2s², 2s2p, 2p², 2s3s, 2s3p, 2s3d, 2p3s, 2p3p, and 2p3d. The intensities for transitions between the lowest 20 levels of these configurations are calculated for an electron temperature equal to half the ionization potential and for electron densities equal to 10¹³, 10¹⁴, and 10¹⁵ cm⁻³.     

Atomic data and spectral line intensities for the boron isoelectronic sequence (Ar XIV through Kr XXXII)

We have calculated the oscillator strengths, radiative decay rates, and the electron collision strenghts for the B-like ions Ar XIV, Ti XVIII, Fe XXII, Ge XXVIII, and Kr XXXII. The corresponding atomic data for the ions Ca XVI, Cr XX, Ni XXIV, Zn XXVI, and Se XXX are determined by interpolation. The configurations included in the calculation are 2s²2p, 2s2p², 2p³, 2s²3s, 2s²3p, and 2s²3d. Using both the computed and the interpolated atomic data, we calculated the populations of the 20 levels belonging to these configurations. The intensities of the transitions are presented for electron densities of interest for the diagnosis of tokamak plasmas (10¹³, 10¹⁴, and 10¹⁵ cm⁻³).     

Atomic data and spectral line intensities for the neon isoelectronic sequence (Si V through Kr XXVII)

The electron impact collision strengths and the spontaneous radiative decay rates are presented for the following ions of the Ne isoelectronic sequence: Si V, Ar IX, Ti XIII, Fe XVII, Ge XXIII and Kr XXVII. Data are given for the 27 levels that belong to four different configurations (2s²2p⁶, 2s²2p⁵3s, 2s²2p⁵3p, and 2s²2p⁵3d). By use of the atomic data calculations of the above-mentioned ions, the atomic data for all the ions with 14 ? Z ? 36 have been interpolated. Energy levels and level populations are presented for all the even-Z ions with 14 ? Z ? 36 (Si V, S VII, Ar IX, Ca XI, Ti XIII, Cr XV, Fe XVII, Ni XIX, Zn XXI, Ge XXIII, Se XXV, and Kr XXVII). The level populations are given for the three electron densities 10¹³, 10¹⁴, and 10¹⁵ cm^?3. Spectral line intensities are also presented for all transitions with intensities within two orders of magnitude of the most intense line in each ion.     

Atomic data and spectral line intensities for S XIII

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for S XIII. The configurations used are 2s², 2s2p, 2p², 2l3l′, 2l4l′ and 2s5l′, with l = s, p and l′ = s, p, d, giving rise to 92 fine-structure levels in intermediate coupling. Collision strengths are calculated at seven incident energies (10, 20, 45, 90, 135, 180, and 225 Ry) for the transitions within the three lowest configurations, and five incident energies (45, 90, 135, 180, and 225 Ry) for transitions between the lowest five levels and the n = 3, 4, 5 configurations. Calculations have been carried out using the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates of the present work, and R-matrix results for the 2s², 2s2p, 2p² configurations available in the literature, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10⁸-10¹⁴ cm⁻³ at an electron temperature of log T_e(K) = 6.4, corresponding to the maximum abundance of S XIII. Spectral line intensities are calculated, and their diagnostic relevance is discussed. Observed line ratios indicate electron temperatures of the emitting plasma close to log T_e(K) = 6.4. This dataset will be made available in the next version of the CHIANTI database.     

Atomic data and spectral line intensities for Ar XI

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Ar XI. The configurations used are 2s²2p⁴, 2s2p⁵, 2p⁶, 2s²2p³3s, 2s²2p³3p, and 2s²2p³3d giving rise to 86 fine-structure levels in intermediate coupling. Collision strengths are calculated at five incident energies (30, 60, 90, 120, and 150 Ry) in the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10⁸-10¹⁴ cm⁻³ at an electron temperature of log T_e (K) = 6.3, corresponding to the maximum abundance of Ar XI. Relative and absolute spectral line intensities are calculated, and their diagnostic relevance is discussed. This dataset will be made available in the next version of the CHIANTI database.     

Atomic data and spectral line intensities for Ar XV

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Ar XV. The configurations used are 2s², 2s2p, 2p², 2l3l^′, , with giving rise to 92 fine-structure levels in intermediate coupling. Collision strengths are calculated at eight incident energies (10, 20, 30, 60, 120, 180, 240, and 300 Ry) for transitions within the three lowest configurations, and five incident energies (60, 120, 180, 240, and 300 Ry) for transitions between the lowest five levels and the n = 3, 4, 5 configurations, using the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates of the present work, and R-matrix results for the 2s², 2s2p, 2p² configurations available in the literature, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10⁸-10¹⁴ cm⁻³ at an electron temperature of , corresponding to the maximum abundance of Ar XV. Spectral line intensities are calculated, and their diagnostic relevance is discussed. Observed line ratios indicate electron temperatures of the relevant emitting plasma close to . This dataset will be made available in the next version of the CHIANTI database.     

Atomic data and spectral line intensities for Mg IX

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Mg IX. The configurations used are 2s², 2s2p, 2p², 2l3l′, 2l4l′ and 2s5l′, with l = s, p and l′ = s, p, d giving rise to 92 fine-structure levels in intermediate coupling. Collision strengths are calculated at seven incident energies (6, 12, 25, 50, 75, 100, and 125 Ry) for the transitions within the three lowest configurations, and five incident energies (25, 50, 75, 100, and 125 Ry) for transitions between the ground configuration and the n = 3, 4, 5 configurations. Calculations have been carried out using the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates of the present work, and R-Matrix results for the 2s², 2s2p, 2p² configurations available in the literature, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10⁸-10¹⁴ cm⁻³ at an electron temperature of log T_e (K) = 6.0, corresponding to the maximum abundance of Mg IX. Spectral line intensities are calculated, and their diagnostic relevance is discussed. Observed line ratios indicate electron temperatures of the emitting plasma which agree with log T_e (K) = 6.0. This dataset will be made available in the next version of the CHIANTI database.     

Atomic data and spectral line intensities for Ni XXV

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Ni XXV. The configurations used are 2s²,2s2p,2p²,2l3l^′,2l4l^′, and 2s5l^′, with l=s,p and giving rise to 92 fine-structure levels in intermediate coupling. Collision strengths are calculated at seven incident energies (50, 100, 150, 225, 300, 375, and 450 Ry) for the transitions within the three lowest configurations corresponding to the 10 lowest energy levels, and at five incident energies (150, 225, 300, 375, and 450 Ry) for transitions between the lowest five levels and the configurations. The calculations are carried out using the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates of the present work, statistical equilibrium equations for level populations are solved at electron densities covering the range at an electron temperature of , corresponding to the maximum abundance of Ni XXV. Spectral line intensities are calculated, and their diagnostic relevance is discussed. This dataset will be made available in the next version of the CHIANTI database.     

Atomic data and spectral line intensities for Mg V

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Mg V. The configurations used are 2s²2p⁴, 2s2p⁵, 2p⁶, 2s²2p³3s, 2s²2p³3p, and 2s²2p³3d, giving rise to 86 fine-structure levels in intermediate coupling. Collision strengths are calculated at five incident energies, 10, 20, 30, 40, and 50 Ry, in the distorted wave approximation. Excitation rate coefficients (not tabulated here) are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. To calculate excitation rate coefficients, collision strengths at low and high energy limits are calculated by a method described by Burgess and Tully. Using the excitation rate coefficients and the radiative transition rates, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10⁸-10¹⁴ cm⁻³ at an electron temperature of log T_e = 5.4, corresponding to the maximum abundance of Mg V. Fractional level populations and relative spectral line intensities are also calculated. Our calculated intensities are compared with the active region observations from the solar EUV rocket telescope and spectrograph (SERTS) and the diagnostic properties of Mg V are discussed. This dataset will be made available in the next version of the CHIANTI database.     

Atomic data and spectral line intensities for Ni XIV

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Ni XIV. We include in the calculations all the configurations belonging to the n=3 complex, and provide data for the lowest 143 fine-structure levels, belonging to the configurations 3s²3p³, 3s3p⁴, 3s²3p²3d, 3p⁵, 3s3p³3d, and 3s²3p3d². Collision strengths are calculated at six incident energies for all transitions: 0.112, 8.07, 21.3, 43.4, 80.3, and 141.8 Ry above the threshold of each transition. Calculations have been carried out using the Flexible Atomic Code. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates of the present work, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10⁸-10¹⁴ cm⁻³ and at an electron temperature of , corresponding to the maximum abundance of Ni XIV. Spectral line intensities are calculated, and their diagnostic relevance is discussed. This data set is available in version 6.0 of the CHIANTI database.     

Atomic data and spectral line intensities for Ca XVII

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Ca XVII. The configurations used are 2s², 2s2p, 2p², 2l3l^′, 2l4l^′ and 2s5l^′, with l=s,p, and l^′=s,p,d giving rise to 92 fine-structure levels in intermediate coupling. Collision strengths are calculated at seven incident energies (15, 30, 75, 112.5, 150, 187.5 and 225 Ry) for the transitions within the three lowest configurations corresponding to the 10 lowest energy levels, and at five incident energies (75, 112.5, 150, 187.5 and 225 Ry) for transitions between the lowest five levels and the n=3,4,5 configurations. Calculations have been carried out using the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates of the present work, and R-Matrix results for the 2s², 2s2p, 2p² configurations available in the literature, statistical equilibrium equations for level populations are solved at electron densities covering the range of at an electron temperature of logT_e(K)=6.7, corresponding to the maximum abundance of Ca XVII. Spectral line intensities are calculated, and their diagnostic relevance is discussed. This dataset will be made available in the next version of the CHIANTI database.     

Atomic data and spectral line intensities for Mg VI

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Mg VI. The configurations used are 2s²2p³, 2s2p⁴, 2p⁵, 2s²2p²3s, 2s²2p²3p, and 2s²2p²3d, giving rise to 72 fine-structure levels in intermediate coupling. Collision strengths are calculated at five incident energies, 12, 24, 36, 48, and 60 Ry. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10⁸-10¹⁴ cm⁻³ at an electron temperature of log T_e (K) = 5.6, corresponding to maximum abundance of Mg VI. Relative and absolute spectral line intensities are calculated and compared with observations of a solar active region.     

Atomic data and spectral line intensities for Si XI

Electron impact collision strengths, energy levels, oscillator strengths and spontaneous radiative decay rates are calculated for Si XI. The configurations used are 2s², 2s2p, 2p², 2l3l′, 2l4l′ and 2s5l′, with l = s,p and l′ = s,p,d giving rise to 92 fine-structure levels in intermediate coupling. Collision strengths are calculated at five incident energies (35, 70, 105, 140, and 175 Ry) in the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates of the present work, and R-Matrix results for the 2s², 2s2p, 2p² configurations available in the literature, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10⁸-10¹⁴ cm⁻³ at an electron temperature of log T_e(K) = 6.2, corresponding to the maximum abundance of Si XI. Spectral line intensities are calculated, and their diagnostic relevance is discussed. This dataset will be made available in the next version of the CHIANTI database.     

Atomic data and spectral line intensities for Ni XVII

Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Ni XVII. We include in the calculations the 23 lowest configurations, corresponding to 159 fine-structure levels: 3l3l′, 3l4l″, and 3s5l?, with l, l′ = s, p, d, l″ = s, p, d, f, and l? = s, p, d. Collision strengths are calculated at five incident energies for all transitions at varying energies above the threshold of each transition. One additional energy, very close to the threshold of each transition, has also been included. Calculations have been carried out using the Flexible Atomic Code in the distorted wave approximation. Additional calculations have been performed with the University College London suite of codes for comparison. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates of the present work, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10⁸ − 10¹⁴ cm⁻³ and at an electron temperature of log T_e(K) = 6.5, corresponding to the maximum abundance of Ni XVII. Spectral line intensities are calculated, and their diagnostic relevance is discussed. This dataset will be made available in the next version of the CHIANTI database.     

Energy and cusp-conditions study for the He isoelectronic sequence

We present variational wave functions for He-like atoms with nuclear charge Z=1,…,10. We propose modifications of some usual simple correlated wave functions to account for the integration factor required in the evaluation of atomic ionization and excitation amplitudes with distorted wave methods.We determine the parameters of the trial functions and the resulting energies. We introduce new procedures to test the cusp conditions at the singularities of the Coulomb field.     

Electric-dipole,quadrupole, and magnetic-dipole susceptibilities and shielding factors for closed-shell ions of the He,Ne, Ar,Ni (Cu+), Kr,Pb, and Xe isoelectronic sequences

Theoretical values of electric and magnetic susceptibilities (α₁, α₂, χ₁) and shielding factors (γ₁, γ₂, σ₁) calculated in the relativistic random-phase approximation are presented in tabular form for ions with closed 1s, 2p, 3p, 3d, 4p, 4d, and 5p shells. The table includes all ions in these sequences with nuclear charge up to Z = 56 and a representative selection of ions with 56 < Z ? 92.