Experimental Radiative Lifetimes, Branching Fractions, and Oscillator Strengths for La II and a New Determination of the Solar Lanthanum Abundance
Abstract
Radiative lifetimes, accurate in most cases to +/-5%, from time-resolved laser-induced fluorescence measurements on a slow beam of lanthanum ions are reported for 31 odd-parity levels of La II. Experimental branching fractions for La II from emission spectra covering the near-ultraviolet to the near-infrared are also reported. The spectra were recorded using the US National Solar Observatory 1.0 m Fourier transform spectrometer. The branching fractions are combined with the radiative lifetimes to produce 84 experimentally determined transition probabilities or oscillator strengths, generally accurate to +/-10%, for La II. These new experimental results are compared to older experimental and theoretical results. These data are applied to determine a new value for the solar photospheric lanthanum abundance, <log10ɛ(La)>=1.13, with estimated internal errors of +/-0.03 and external errors of +/-0.03.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 2001
- DOI:
- 10.1086/321549
- Bibcode:
- 2001ApJ...556..452L
- Keywords:
-
- Subject headings: Atomic Data;
- Sun: Abundances