Studies of Landé gJ-factors of singly ionized lanthanum by laser-induced fluorescence spectroscopy

•Slight modification of a hollow-cathode/LIF method for Zeeman effect studies in La ions is presented.•Where a single excited line selected from a very dense spectrum can be easily isolated and analyzed.•Allowing an accurate measurements of the Lande factors for several levels of La II.

Laser-induced fluorescence spectroscopy, using a cooled hollow cathode discharge lamp as source of ions, was used to observe the Zeeman splitting of 18 lines of La II in the wavelength range 629.6-680.9 nm, in external intermediate magnetic fields up to 800 G. The recorded hyperfine-Zeeman patterns were analyzed in detail using already known accurate hyperfine structure A- and B-constants. From the recordings the Landé gJ-factors for some levels belonging to the 5d2, 5d6s, 5d6p, 4f5d, 4f6s and 4f6p configurations of La II were determined. The obtained experimental gJ-factors are compared with earlier measurements and theoretical calculations.