Atomic data from the IRON Project

Abstract

Electron excitation collision strengths of 3d 2 fine-structure transitions in Ca-like Fe vii are calculated using an R-matrix method, which included the 80 terms arising from the 3d 2 , 3d4s, 3d4p, 3d4d, 3d4f and 3p 5 3d 3 configurations. Extensive autoionizing resonance structures together with channel coupling is therefore explicitly included; relativistic effects are accounted for by a term-coupling transformation. A thermal average is taken to obtain the effective fine-structure collision strength as a function of electron temperature T , for log T (K) = 4.3-6. Open 3p-shell resonances are seen to considerably enhance the background collision strength, by several factors for some of the 3d transitions.