EDP Sciences
Free access
Volume 430, Number 2, February I 2005
Page(s) 725 - 729
Section Atomic, molecular and nuclear data
DOI http://dx.doi.org/10.1051/0004-6361:20041969

A&A 430, 725-729 (2005)
DOI: 10.1051/0004-6361:20041969

Effective collision strengths for fine-structure transitions for the electron impact excitation of N II

C. E. Hudson and K. L. Bell

Department of Applied Mathematics and Theoretical Physics, The Queens University of Belfast, Belfast BT7 1NN, Northern Ireland, UK
    e-mail: c.hudson@am.qub.ac.uk

(Received 7 September 2004 / Accepted 28 September 2004 )

We present effective collision strengths for the electron impact excitation of singly ionized nitrogen which have been calculated using the R-matrix method. The 23 lowest LS states are included in the expansion of the total wavefunction. These target states arise from the 2s 22p 2, 2s2p 3 and 2s 22p3 l( $l={\rm s,p,d})$ configurations, leading to 41 fine structure levels and 820 possible transitions. The fine-structure collision strengths were obtained by transforming to a jj-coupling scheme using the JAJOM program of Saraph and have been determined at a sufficiently fine energy mesh to delineate properly the resonance structure. The effective collision strengths were calculated by averaging the electron collision strengths over a Maxwellian distribution of velocities. Tabulations of the non-zero effective collision strengths are given for electron temperatures ( $T_{\rm e}$) in the range $\log_{10} T_{\rm e} ({\rm K}) = 2.0{-}5.5$.

Key words: atomic processes -- line: formation -- methods: analytical

© ESO 2005