Stark broadening and transition probability ratios in the MgI spectrum

Stark widths (W) and shifts (d) of the six astrophysicafly important 285.212, 383.230, 383.829, 516.732, 517.268, and 518.360 nm neutral magnesium (Mg I) spectral lines in the 3s(2) S-1-3p(1)P(0), 3p(3)P(0)-3d(3)D and 3p(3)P(0)-4s(3)S transitions have been measured in laboratory helium plasma at about 50000 K electron temperature and 1 x 10(23) m(-3) electron density. They represent the first measured values and, also, the first experimental W and d data in the mentioned transitions. Using the relative line intensity ratios of the lines in the mentioned transitions we have obtained the ratios of corresponding transition probability values (Einstein's A values). They represent the first experimental data based on the analysis of the Mg I emission spectral lines. We have found agreement with theoretical transition probability ratios tabulated by NlST.