Selected Lifetime and Oscillator Strength Measurements in Si II

We have remeasured the lifetimes of the 3s24s and 3s25s2S1/2 levels in Si II using beam foil spectroscopic techniques. Measured values for the lifetimes and oscillator strengths derived from them are presented and compared with previous measurements and theoretical calculations. Agreement with recent theoretical calculations is now quite good: for 3s24s it is excellent and for 3s25s it is satisfactory, although the theoretical uncertainties in that calculation are still somewhat larger than desired.