Electron-impact excitation cross sections of triplet levels of magnesium atom

The method of extended crossing beams is used to study electron-impact excitation of triplet levels of magnesium atom. The excitation cross sections and the optical excitation functions of the investigated spectral lines are measured. It is found that, as the principal quantum number of the upper level increases, the excitation cross sections in the spectral series decrease by a power law. The numerical values of the parameters characterizing the power function are determined for seven spectral series.