Hyperfine structure studies of the odd-parity electronic levels of the terbium atom

Abstract In this work the hyperfine structure of 43 odd-parity levels of the terbium atom was investigated with the method of laser induced fluorescence in a hollow cathode discharge. Altogether 73 spectral lines were examined, with the odd-parity levels involved as the upper levels. For 41 levels the constants A and B were determined for the first time, and for the remaining two levels improved values could be obtained due to the supplementary measurements performed. As a by-product, also the hyperfine structure constants for two lower even-parity levels could be corrected. The obtained results concerning the odd-parity levels contributed to considerable extension of the available database of the hyperfine structure constants for the atomic terbium; they would be included in the semi-empirical analysis of the fine and the hyperfine structure for the odd-parity configurations system, planned in our research group.