Use of the R-matrix method for bound-state calculations. II. Results for energy levels of C+

Accurate R-matrix calculations for collisional excitation of C 2+ , with inclusion of all C 2+ levels with configurations 2s 2 , 2s2p and 2p 2 , have been made previously by Berrington et al. (1985). The R-matrix data obtained in that work have now been used to calculate energies, in the frozen-cores (FCS) approximation, for 140 terms of C + (of which 127 give bound states and 13 give autoionising states). There is good agreement with experiment for all of the 83 terms for which experimental energies have been determined. There is also close agreement with energies for 15 terms calculated by Nussbaumer and Storey (1981) who used a similar FCS approximation but completely different numerical methods. The main new feature of the present work is in the use of methods which are very fast and completely automatic and hence convenient for the computation of large amounts of spectroscopic data.