Radiative-lifetime measurements for Si iii 3s4s^3S, S v 3s4f^3F^0, and Si iv and S vi 4f^2F^0

The beam-foil technique has been used to measure radiative lifetimes for the upper states of the transitions 3s3p3P0-3s4s3S in Si iii (996 Å), 3s3d3D-3s4f3F0 in S v (568 Å), and 3d2D-4f2F0 in Si iv (1067 Å) and S vi (465 Å). Absorption oscillator strengths derived from the lifetime values are compared with theoretical and experimental results for analogous transitions in atomic systems of the Na i and Mg i isoelectronic sequences. Discrepancies between experiment and theory have been reduced for the Si iii, Si iv, and S vi transitions. The S v result reflects effects of configuration interaction in magnesiumlike systems.