Paper XXXI

Electron impact excitation of optically allowed and intercombination electric dipole transitions in Fe XII

A.M. Binello, H.E. Mason and P.J. Storey

Astronomy & Astrophysics Supplement Series, 1998, Vol.131, pp.153-166

A new, accurate set of electron impact collisional data is presented, relating to all electric dipole fine-structure transitions between the ground 3s$^2$3p$^3$ and the first two excited 3s3p$^4$, 3s$^2$3p$^2$3d configurations in Fe XII (Fe$^{11+}$). Theoretical energies have been obtained with a multi-configuration atomic structure calculation. The R-matrix method, coupled with the Coulomb-Bethe (CBe) approximation for the high partial wave contributions to the collision strengths, has been employed in the Fe$^{11+}$ - e$^-$ scattering problem. The data presented in this paper form part of the IRON Project effort to provide the most accurate atomic data available for all the iron ions (Hummer et al. 1993).