Astron. Astrophys. Suppl. Ser. 142, 85-94

Recombination coefficients for C II lines

A.R. Davey ¹ - P.J. Storey ² - R. Kisielius ²

Send offprint request: P.J. Storey

1 - Department of Physics, Montana State University, Bozeman, MT 59717-3840, U.S.A.
e-mail: ard@filament.physics.montana.edu
2 - Department of Physics and Astronomy, University College London, Gower St., London, WC1E 6BT, UK
e-mail: rk@star.ucl.ac.uk, pjs@star.ucl.ac.uk

Received July 20; accepted October 4, 1999

Abstract:

Effective recombination coefficients are given for C II transitions between doublet states. The calculations are carried out in the temperature range $500 - 20\,000\;{K}$ and for an electron density of 10⁴ cm^-3. The effects of electron collisions on the excited states are included. The necessary bound-bound and bound-free radiative data are obtained from a new R-matrix calculation in which photoionization resonances are fully delineated, thereby accurately incorporating the effects of both radiative and dielectronic recombination. The R-matrix calculation includes all bound states with principal quantum number $n \leq 15$ and total orbital angular momentum $L \leq 4$. The effect of moving the resonance features to their experimentally determined positions is also investigated and found to be important at low temperatures.

Key words: atomic data -- line: formation -- H II regions -- planetary nebulae: general