Stark broadening parameters in the MnI spectrum

The shapes and shifts of the astrophysically interesting neutral manganese (Mn 1) resonance spectral lines (403.075, 403.306 and 403.448 nm) have been observed in the laboratory helium plasma at a 47 000 K electron temperature and 6.6 X 10(22) m(-3) electron density. At the mentioned plasma parameters the Stark broadening has been found as important mechanism in the Mn I line shape formation. Our measured Mn I Stark widths (W) and shifts (d) are the first data in the literature. The W values are compared with Splitting (Delta(hfs),) in the hyperfine structure (hfs). At the above mentioned helium plasma conditions the line splitting in a hyperfine structure has been overpowered by Stark and Doppler broadenings in the case of the investigated Mn I lines. We have found negative line shifts that lie into the hfs splittings.