Hyperfine structure investigations of Mn I

•Hyperfine structure (hfs) of 30 spectral lines in atomic manganese (Mn I) was recorded.•For 3 odd-parity and 15 even-parity levels both hfs constants A and B were determined for the first time.•For another 8 levels new constants B were evaluated.•Semi-empirical analysis of the even-parity level system in Mn I was performed•Good consistency was found between the experimental hfs constants and the semi-empirical fit In this work the hyperfine structure (hfs) of 30 spectral lines of the manganese atom was investigated with the method of laser induced fluorescence in a hollow cathode discharge with spectral selection of the fluorescence channels. As a result, the hyperfine structure constants A and B for altogether 12 odd-parity and 16 even-parity levels were determined. For 3 odd-parity and 15 even-parity levels the A and B values are reported for the first time, for another 8 levels new constants B were evaluated, and for the remaining 8 levels the accuracy of the hitherto available literature data was improved; in some cases, where discrepancies between the earlier experimental results, obtained by other authors, and the theoretical predictions were observed, the new data constituted an unequivocal verification, which data are correct. The available database of the hyperfine structure constants for the manganese atom was thus further extended. Semi-empirical parametrization of the hyperfine structure for the even-parity level system of the atomic manganese were also performed in the present work; the consistency between the experimental and semi-empirically predicted hfs constants was found generally satisfactory, and in many cases even very good.