Energy Levels and Magnetic Dipole Transitions in the 4p^4 Ground Configuration of Singly Ionized Atomic Bromine (Br ii)

Abstract

Improved values of the previously known Br ii energy levels relative to the 4p43P2 ground level at 0.0 cm−1 have been obtained from preliminary observations in the vacuum ultraviolet region. The position of the 4p41S0 level was found from the “forbidden” transition, 4p43P1−4p41S0 at 4042.42 A. An observation of the transverse Zeeman effect for this line yields a Lorentz triplet with the usual polarizations reversed and approximately the expected splitting. It is thus confirmed that the line arises from magnetic dipole radiation. A similar line at 8269.65 A, due to the transition 4p43P2−4p41D2, shows hyperfine-structure broadening consistent with the calculated structure. New values for the levels of 4p4 are: 3P1 = 3136.4 cm−1, 3P0 = 3837.5 cm−1, 1D2 = 12 089.1 cm−1, and 1S0 = 27867.1 cm−1. The values for all levels above 4p4, as given in Atomic Energy Levels, Vol. II, should be reduced by 5.9 ± 0.5 cm−1. Intermediate-coupling parameter values which yield a good fit for Br ii4p4 are F2(4p,4p)=1690cm−1 and ζ(4p)=2800cm−1.