Revised level energies of Sc I derived from Fourier transform spectra considering hyperfine structure

• The center of gravity wavelengths and wave numbers of 814 lines were determined considering their hyperfine structure patterns. • The hyperfine structure constants A of 36 high-lying levels are given for the first time. • In a least squares fit revised level energies of the Scandium atom (Sc I) are calculated. • Deviations between measured and calculated wave numbers are for most lines below 0.005 cm -1 . • The investigation caused some changes of line classifications in the NIST ASD databank. The determination of the center of gravity (cg) wavelengths of spectral lines, showing wide hyperfine (hf) structure patterns, is challenging. The lowest uncertainties are observed if the hf structure constants of the combining energy levels are available, and the cg wavelengths are determined by fitting the hf patterns. For the majority of the Sc I levels these constants are either known from literature or they could be determined within this work. The A -constants of 36 levels are reported in this work for the first time, for 9 levels the literature values were revised. Using new determined wavelengths from calibrated FT spectra, we were able to revise the energy values of 138 even-parity levels and 99 odd-parity levels. The energy corrections are on the order of 0.050 cm -1 . For several levels detailed considerations were made. Some lines, given in the Atomic Spectra Database (ASD) of the National Institute of Standards and Technology (NIST), have been re-classified, and for some doubly classified wavelengths we could decide which classification is correct. Some peculiarities concerning deviations of observed hyperfine patterns from simulated patterns, using theoretical intensity ratios, are mentioned.