We report lifetimes, branching fractions, and the resulting oscillator strengths for transitions within the P II multiplet (3s 2 3p 2 3 P − 3s3p 3 3 P o ) at 1308 Å. These comprehensive beam-foil measurements, which are the most precise set currently available experimentally, resolve discrepancies involving earlier experimental and theoretical results. Interstellar phosphorus abundances derived from λ1308 can now be interpreted with greater confidence. In the course of our measurements, we also obtained an experimental lifetime for the 3p4s 3 P o 0 level of P IV. This lifetime agrees well with the available theoretical calculation.

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We present lifetime measurements using beam-foil techniques for radiative transitions from the 3p 4 ( 1 S)4s 2 S 1/2 , 3p 4 ( 3 P )5s 2 P 1/2,3/2 , and 3p 4 ( 3 P )3d 2 F 5/2 levels in Cl I and the corresponding results of the oscillator strengths for transitions at 1004.68, 1079.88, 1090.73, and 1094.77Å, respectively. We compare our experimental results with available theoretical calculations and astronomical observations in an effort to resolve discrepancies among them.

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