Oscillator Strengths for Ultraviolet Transitions in P II -The Multiplet at 1308 {\AA}

TL;DR

This paper provides precise experimental oscillator strengths and lifetimes for ultraviolet P II transitions at 1308 Å, resolving previous discrepancies and improving interstellar phosphorus abundance measurements.

Contribution

It presents the most accurate beam-foil measurements of P II oscillator strengths and lifetimes, clarifying earlier experimental and theoretical inconsistencies.

Findings

Resolved discrepancies in P II oscillator strengths.

Provided accurate interstellar phosphorus abundance data.

Measured P IV lifetime consistent with theory.

Abstract

We report lifetimes, branching fractions, and the resulting oscillator strengths for transitions within the P II multiplet (3s23p2 3P - 3s3p3 3Po) at 1308 {\AA}. 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 {\lambda}1308 can now be interpreted with greater confidence. In the course of our measurements, we also obtained an experimental lifetime for the 3p4s 3P0o level of P IV. This lifetime agrees well with the available theoretical calculation.