Paper XXXVIII

Electron impact excitation of the fine-structure transitions in the $n=3$ complex of Fe XV

W.Eissner, M.E. Galavis, C. Mendoza and C.J. Zeippen

Astronomy & Astrophysics Supplement Series, 1999, Vol.137, pp.165-173

As part of a systematic study of the collisional properties of Fe ions carried out by the IRON Project, electron excitation rates (effective collision strengths) are computed for all the fine-structure transitions within the $n=3$ complex of Fe XV in the electron temperature range $10^5\le T/K \le 10^7$. Configuration-interaction target wavefunctions are generated with the atomic structure code SUPERSTRUCTURE, and collision strengths are computed in the close-coupling approximation with a Breit-Pauli R-matrix package. Special care is taken to resolve the resonance structure and to ensure the convergence of the partial wave expansion, specially for dipole allowed transitions. By comparing with previously calculated collision strengths in the distorted wave approximation, a 20% accuracy rating is assigned to transitions with effective collision strengths $\Upsilon(T)\ge 10^{-2}$.