Astron. Astrophys. Suppl. Ser. 131, 153-166

Atomic data from the IRON project

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

A.M. Binello¹ - H.E. Mason¹ - P.J. Storey²

Send offprint request: A. Binello

1 - Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, UK
2 - Department of Physics and Astronomy, University College London, Gower Street, London WC1 E6BT, UK

Received January 9; accepted February 24, 1998

Abstract:

A new, accurate set of electron impact collisional data is presented, relating to all electric dipole fine-structure transitions between the ground 3s²3p³ and the first two excited 3s3p⁴, 3s²3p²3d configurations in FeXII (Fe¹¹⁺). 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 Fe¹¹⁺ - $\rm e^-$ scattering problem. The data presented in this paper form part of the IRON Project effort to provide the most accurate atomic data available to date for all the iron ions (Hummer et al. 1993).

Key words: ion -- atomic data -- atomic processes -- Sun: UV radiation