On the Common Influence of Stark Broadening and Hyperfine Structure in Stellar Spectra: Mn II Lines

Ionized manganese lines are of interest for the analysis and modelling of stellar spectra as well as for the modelling and consideration of sub photospheric layers. Recently, a disagreement of up to 5.7 times is found between experimental and calculated Stark widths and shifts of Mn II lines. As one of possible reasons, the hfs splitting was assumed. In order to investigate the reasons for this, we performed more sophisticated calculations for two Mn II lines, by using the semiclassical perturbation theory. Moreover, we made a detailed analysis of the influence of hfs splitting on the considered experimental results. Also, the obtained results were used for the investigation of the influence of Stark broadening on Mn II spectral line profiles in DB white dwarfs. It was demonstrated the importance to take into account Stark broadening mechanism for the analysis of DB white dwarf spectra. The obtained data and conclusions are of interest for a number of problems in stellar and Solar physics, like spectrum analysis and synthesis, radiative transfer and modelling of sub photospheric layers.