Energy levels and radiative transitions of Mg VII and Si IX

Term energies, line strengths, transition probabilities, and transition wavelengths among the (1s(2))2s(2)2p(2), 2s(2)2p3p, 2s(2)p3, 2s(2)2p3s and 2s(2)2p3d (1,3,5) L (L = S, P, D, F) configuration states in Mg VII and Si IX are calculated by using the multiconfiguration Rayleigh-Ritz variation method and restricted variation method. The transition line strengths and transition probabilities of the electric dipole transitions are both given in length and velocity gauges. Differences between these two gauge values are discussed. The calculated atomic parameters show good agreement with the observed experimental results and other theoretical data. Furthermore, the uncertainty of each electric dipole transition line strength is estimated. For several transition parameters, uncertainties are decreased compared to the values from the National Institute of Standards and Technology Atomic Spectra Database.