Hyperfine Structure Investigation of Singly Ionized Thulium in Fourier-transform Spectra

Abstract The hyperfine structure of 40 spectral lines of singly ionized thulium (Tm ii ) in emission spectra from a hollow cathode discharge lamp measured with a Fourier transform spectrometer in the wavelength range from 335 to 2345 nm has been investigated. As a result of the analysis, the magnetic dipole hyperfine structure constants A for 27 fine structure levels of Tm ii were determined for the first time. In addition, the values of two magnetic dipole hyperfine structure constants A from the literature were declared incorrect, and the corrected values were given.