Abstract
Energy levels and oscillator strengths for the first five elements of the carbon isoelectronic sequence (C I, N II, O III, F IV and Ne V) have been calculated using the Hartree-Fock pseudo-relativistic (HFR) and the Thomas-Fermi-Dirac-Amaldi (TFDA) approaches. The configuration expansion containing the eight configurations, 2s(2) 2p(2), 2s 2p(3), 2s(2) 2p 3s, 2s(2) 2p 3p, 2s(2) 2p 3d, 2s(2) 2p 4s, 2s(2) 2p 4p and 2s(2) 2p 5s, has been used. Our presented results have been compared with other theoretical and experimental data. The analysis of the weighted oscillator strengths trends allows us to estimate values of missing data along this isoelectronic sequence. We present an analytic form of the weighted oscillator strengths and give an example of its use for interpolating and extrapolating values for the carbon isoelectronic sequence.