This article has an erratum: [https://doi.org/10.1051/0004-6361/200810055e]
Volume 486, Number 2, August I 2008
|629 - 636
|Atomic, molecular, and nuclear data
|22 May 2008
Electron impact excitation collision strength for transitions in C II*
Department of Physics, Clark Atlanta University, Atlanta, GA 30314, USA e-mail: firstname.lastname@example.org
Accepted: 20 May 2008
Aims. Oscillator strengths and electron impact excitation collision strengths for C II lines among the fine-structure levels are calculated. Thermally averaged collision strengths are presented as a function of electron temperature for application to astrophysical plasmas.
Methods. An accurate description of the target wave functions has been obtained in the multiconfiguration Hartree-Fock approach with flexible non-orthogonal orbitals. The 42 fine-structure levels of the 2s22p, 2s2p2, 2s23l (), 2p3, 2s24l (–3), 2s2p3s and () configurations have been included in the scattering calculation. A second calculation with lowest 35 levels in the close-coupling expansion has also been carried out to check channel coupling effects on collision strengths. The continuum functions have been represented by the use of B-spline basis. The B-spline R-matrix method in the framework of Breit-Pauli approximation has been used to investigate the electron impact excitation of forbidden and allowed transitions in C II.
Results. The present cross sections for the resonance 2P°–2s2pD, 2S and intercombination 2P°–2s2p2 4P transitions are in very good agreement with the electron energy-loss merged-beams experiment. Oscillator strengths and transition probabilities for C II lines normally compare very well with previous calculation. The effective collision strengths are obtained by integrating total resonant and non-resonant collision strengths over a Maxwellian distribution of electron energies and these are presented over a wide temperature range suitable for modeling of astrophysical plasmas. Our effective collision strengths show significant differences with those from previous calculations for transitions involving higher excitation levels.
Key words: atomic data / atomic processes
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.