  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 nm 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.
