Beam-foil spectroscopy of bromine from 450 to 1000 Å

Abstract

Beam-foil excitation of the bromine spectrum has been applied to the measurement of radiative lifetimes for eight terms in BrV to Br VII, using HBr+ ions of energy 0.5–1.6 MeV. The multiplet ƒ values derived from these results are found to be reasonably consistent with other measurements for the analogous transitions in homologous atoms, except for the 4s4p22D term in BrV, where configuration interaction is known to be important. Agreement within a factor of two is found with ƒ values forecast by calculations based upon the Coulomb approximation. The behavior of the ƒ values of the 4s21S-4s4p1P0 and 4s4p3P0-4s4d3D transitions along the Zni isoelectronic sequence is considered in detail, and again the experimental results are consistent with each other but differ from ƒ values calculated by several techniques by a factor of about two. Many previously unclassified lines have been observed, and tentative assignments are suggested for five of these. Decay curves have also been recorded for nine spectral features in the region 550–650 Å, which suggest that the 1P0, 1D0, 3P0, and 3D0 terms of the 4p4d configuration in Br IV all have lifetimes in the range 0.08–0.14 ns.