Atomic data for opacity calculations. V. Electron impact broadening of some C III lines

For pt.IV see ibid., vol.20, p.6409-29 (1987). Parameters determining the shifts and widths of the C III lines 2s 2 1 S-2s2p 1 P o , 2s2p 3 P o -2p 2 3 P, 2s2p 1 P o -2p 2 1 D and 2s2p 1 P o -2p 2 1 S are calculated using the impact approximation of Baranger (1958) and accurate close-coupling calculations for the (C III+e) collision problem. It is shown that neglect of the elastic scattering term in the expression of Baranger leads to underestimation of the line widths by factors ranging from 0.79 to 0.45. Results are compared with those given by an effective Gaunt factor approximation.