Atomic data from the IRON project^*

LXVII. Electron impact excitation of Fe XIII

¹ Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK e-mail: pjs@star.ucl.ac.uk
² Observatoire de Paris, UMS 2201, CNRS/INSU, 61 avenue de l'Observatoire, 75014 Paris, France

Received: 12 June 2009
Accepted: 14 December 2009

Abstract

A new R-matrix calculation of rate coefficients for electron collisional excitation of is presented and compared to recent calculations of comparable complexity. At temperatures at which Fe¹²⁺ is typically found in the solar corona, the present results, which use the intermediate coupling frame transformation method, show significant differences compared to some earlier work. We use a large configuration interaction calculation with extensive correlation to assess the accuracy of our and earlier workers' scattering targets.