Electron impact excitation of Fe XIX |

K. Butler and C.J. Zeippen |

Astronomy & Astrophysics, 2001, Vol.372, pp.1083 |

Collision strengths and collisional rate parameters have been calculated for
transitions among 92 n=2 and n=3 levels of O-like Fe XIX. The method used is
the Breit-Pauli R-matrix formalism in which most prominent relativistic effects
are accounted for. Partial wave contributions up to J=59/2 are included
explicitly while ``top-up'' procedures complete the sum to infinity. Several
thousand energy points were used to fully incorporate the effect of resonances
in the collisional cross sections when estimating the collisional rate
parameters. **This is particularly important at lower temperatures
where the resonant contributions dominate**. The present results are
expected to be accurate to better than 20% for transitions among n=2 levels.

2006-10-25