Atomic data and spectral line intensities for S IX
Abstract
Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for the Olike ion S IX. The configurations used are 2s ^{2}2p ^{4}, 2s2p ^{5}, 2p ^{6}, 2s ^{2}2p ^{3}3s, 2s ^{2}2p ^{3}3p, and 2s ^{2}2p ^{3}3d giving rise to 86 finestructure levels in intermediate coupling. Collision strengths are calculated at five incident energies, 25, 50, 75, 100, and 125 Ry. Excitation rate coefficients are calculated by assuming a Maxwellian electron velocity distribution at several electron temperatures in the 5.6 ⩽log T_{e} (K)⩽6.2 range, where S IX is formed. 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 10 ^{8}10 ^{14} cm ^{3}. Relative spectral line intensities are calculated. Proton excitation rates among the lowest three levels have been included in the statistical equilibrium equations. The predicted S IX line intensities are compared with SUMER (SOHO) observations of the quiet Sun.
 Publication:

Atomic Data and Nuclear Data Tables
 Pub Date:
 September 2003
 DOI:
 10.1016/S0092640X(03)000573
 Bibcode:
 2003ADNDT..85..169B