Astron. Astrophys. 345, 663-668 (1999)

Proton impact excitation of the 1s²2s²2p^{2 3}P fine-structure transitions in carbon-like ions

R.S.I. Ryans ¹, V.J. Foster-Woods ¹, R.H.G. Reid ² and F.P. Keenan <sup>1

1</sup> Department of Pure and Applied Physics, Queen's University, Belfast, BT7 1NN, Ireland (R.Ryans, F.Keenan@qub.ac.uk)
² Department of Applied Mathematics and Theoretical Physics, Queen's University, Belfast, BT7 1NN, Ireland (R.Reid@qub.ac.uk)

Received 1 August 1998 / Accepted 22 March 1999

Abstract

We present new cross sections and thermally averaged excitation rate coefficients for proton impact excitation of the 1s²2s²2p^{2 3}P fine-structure transitions for ions in the carbon isoelectronic sequence. These data have been calculated using a close-coupled impact parameter method that incorporates the effects of higher lying levels of the triplet 2s2p³ configuration. We find that the inclusion of these additional states leads to significant reductions in excitation rates for high-Z ions.

Key words: Sun: chromosphere atomic data

Send offprint requests to: R.S.I. Ryans (R.Ryans@qub.ac.uk)

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Contents

• 1. Introduction
• 2. Calculation of cross sections and excitation rate coefficients
• 3. Results
• Acknowledgements
• References

© European Southern Observatory (ESO) 1999

Online publication: April 19, 1999
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