Paper XXXIV

Electron impact excitation of Fe XV.

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

Astronomy & Astrophysics Supplement Series, 1999, (in press)

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 $10^5\leq T/{\rm K}\leq 10^7$. 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 strength in the distorted wave approximation, a 20% accuracy rating is assigned to transitions with effective collision strengths $\Upsilon(T)>10^{-2}$.