Relativistic calculation of 2p53s, 3p and 3d energy levels and transition wavelengths in Ti XIII, Fe XVII and some other neon-like ions

Average energies for the configurations 2p5 3s, 3p and 3d in a number of neon-like ions from Al IV to Xe XLV have been calculated by means of the MCDF computer code of Grant et al. The results have been compared with observations and previous non-relativistic calculations. Fine- structure levels and 3s-3p and ip-3d transition wavelengths have also been calculated with the MCDF code for Ti XIII and Fe XVII, both in the single-configuration approximation and in a multiconfiguration treatment including 2s 2p6 nl. The configuration interaction was found to affect 2p5 3p3S1 most seriously. A separate optimization for the 3p1S0 state was needed, due to the particular radial dependence of this state. The calculated wavelengths show excellent agreement with the observations, and the MCDF calculations are well suited for wavelength predictions in neon-like n = 3 system