Atomic data and spectral line intensities for Ni XXI
Abstract
Electron impact collision strengths, energy levels, oscillator strengths and spontaneous radiative decay rates are calculated for Ni XXI. The configurations used are 2 s^{2}2 p^{4}, 2 s2 p^{5}, 2 p^{6}, 2 s^{2}2 p^{3}3 s, and 2 s^{2}3 p^{3}3 d giving rise to 58 finestructure levels in intermediate coupling. Collision strengths are calculated at five incident energies, 85, 170, 255, 340, and 425 Ry. Excitation rate coefficients are calculated by assuming a Maxwellian electron velocity distribution at an electron temperature of log T_{e}(K)=6.9, corresponding to maximum abundance of Ni XXI. Using the excitation rate coefficients and the radiative transition rates, statistical equilibrium equations for level populations are solved at electron densities 10 ^{8}10 ^{14} cm^{3}. Relative spectral line intensities are calculated. Proton excitation rates between the lowest three levels have been included in the statistical equilibrium equations. The predicted intensity ratios are compared with available observations.
 Publication:

Atomic Data and Nuclear Data Tables
 Pub Date:
 March 2003
 DOI:
 10.1016/S0092640X(03)000111
 Bibcode:
 2003ADNDT..83...71B