Atomic data and spectral line intensities for Ca IX
Abstract
Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for Ca IX. We include in the calculations the 33 lowest configurations in the n=3,4, and 5 complexes, corresponding to 283 finestructure levels in the 3l3l', 3l4l'', and 3l5l''' configurations, where l=s,p,d, l^{″}=s,p,d,f and l^{‴}=s,p,d,f,g. Collision strengths are calculated at five incident energies for all transitions: 5.8, 13.6, 24.2, 38.6, and 57.9 Ry above the threshold of each transition. An additional energy, very close to the transition threshold, has been added, whose value is between 0.0055 Ry and 0.23 Ry depending on the levels involved. Calculations have been carried out using the Flexible Atomic Code and 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 calculated in the present work, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10^{8}10^{14} cm^{3} and at an electron temperature of logT_{e} (K)=5.8, corresponding to the maximum abundance of Ca IX. Spectral line intensities are calculated, and their diagnostic relevance is discussed.
 Publication:

Atomic Data and Nuclear Data Tables
 Pub Date:
 November 2014
 DOI:
 10.1016/j.adt.2014.03.002
 Bibcode:
 2014ADNDT.100.1519L