Oscillator Strengths for Ultraviolet Transitions in P ii: The Multiplet at 1308 ?

摘要

We report lifetimes, branching fractions, and the resulting oscillator strengths for transitions within the P?ii multiplet (3s 23p 2 3 P–3s3p 3 3 P o) at 1308 ?. 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 level of P?iv. This lifetime agrees well with the available theoretical calculation.