Systematic investigations of the hyperfine structure constants of niobium I levels. Part II: Constants of upper odd parity energy levels between 31,056 and 42,000 cm−1 and discovery of two new levels

Abstract

The present paper is the continuation of the systematic investigation of the hyperfine (hf) structure of atomic Niobium presented in Part I of this work. Just like in Part I, spectral lines in the wavelength region between 5540 and 6570 Å were investigated by laser-induced fluorescence spectroscopy. From altogether about 380 transitions, about 190 are treated in this part. Here, we report on transitions between lower even parity levels between 13,515 and 23,048 cm-1 and upper odd parity levels between 31,025 and 42,000 cm−1. Most of the hyperfine structure constants of the involved levels could be determined with lower uncertainty compared to literature values. Additionally, the discovery of two previously unknown energy levels is reported: one level of even parity at 21,182.31 cm−1, J = 5/2, as well as one level of odd parity at 39,834.88 cm−1, J = 13/2.