Far Ultraviolet Absorption Spectrum of Magnesium

The transmissivity of magnesium has been measured over the spectral range from 220 Å to 750 Å. The linear absorption coefficient is nearly free from structure and is of the order of magnitude of ${10}^4$ to ${10}^5$ ${\mathrm{cm}}^{-1\mathrm{}}$ over this spectral region. The dominant absorption mechanism is interband excitation. Treating the valence electrons of magnesium by a nearly free-electron approximation yields semiquantitative agreement with the observed absorption spectra.