Investigation of the Zeeman—hyperfine structure of atomic niobium

Highlights: • Laser induced fluorescence (LIF) method and optogalvanic spectroscopy (OG) were used in measurements of the Zeeman-hf structure of atomic niobium. • New experimental gJ factors have been determined for 10 energy levels of Nb I. • Hfs and $g_J$ data for many other levels of Nb I have been tested and verified. • In the computer analysis of the spectra the saturation effect was taken into account. Laser spectroscopy was used for the investigation of the Zeeman-hf structure of 22 lines of atomic niobium in the visible region between 573.7 and 649.4 nm. We used two methods of laser absorption spectroscopy: laser induced fluorescence (LIF) method and optogalvanic spectroscopy (OG). The source of niobium atoms was a hollow cathode discharge tube. The magnetic field of approximately 800 G was generated by a permanent neodymium magnet. We determined experimentally for the first time the Lande $g_J$ factors for 10 levels. We also verified earlier experimental data on the hf structure as well as data from the NIST database regarding Lande $g_J$ factors.