The Optical Properties and the Band Structure of Magnesium Chloride

The optical properties of MgCl 2 have been studied by means of reflection spectra in the region from VUV to XUV, absorption spectra in the VUV region, XPS and UPS spectra. In order to interpret the experimental results, the electronic band structure of MgCl 2 has been calculated by means of the tight binding method for the core and valence band states and the plane wave method based on the empty lattice model for the conduction band states. The obtained band structure is found to well explain the experimental results. Therefore, it is found that the top of the valence band is composed of two almost degenerate states, i.e. \(⁻₃\) and \(⁻₂\). The polarization effect of the anisotropic crystal MgCl 2 which has the CdCl 2 layer type crystal structure is expected to appear at tlte Z points of the Brillouin zone.