Laser spectroscopic investigation of atomic holmium in the wavelength range from 780 nm to 830 nm: Hyperfine structure measurements and a new energy level

The hyperfine structure of neutral holmium was studied using a hollow cathode discharge lamp and laser-induced fluorescence spectroscopy or optogalvanic spectroscopy, respectively. Altogether 42 spectral lines in the wavelength range from 780 nm to 830 nm were investigated. Magnetic dipole hyperfine structure constants A and electric quadrupole hyperfine structure constants B were determined for 23 levels of even parity and for 25 levels of odd parity. Eight of the reported hyperfine structure constants have not been published before. For most other levels, previously published hyperfine structure constants have been measured with greater precision. Additionally, one new energy level 29013.43 cm(-1) with odd parity and J = 13/2 has been discovered. (C) 2019 Elsevier Ltd. All rights reserved