Parameters of the energy spectrum of layered crystals $CdI_2$

The pseudopotential method in the nonlocal approximation is used to calculate the band dispersion in strongly anisotropic wide-band crystals $CdI_2$. From the optical reflection spectra obtained using the synchrotron radiation, we calculate the real ($\epsilon _1$) and imaginary ($\epsilon _2$) parts of the dielectric permittivity at T = 77 К by the Kramers-Konig method. We calculate the band structure of the $CdI_2$ crystals and identify the interband optical transitions from the concrete points of the Brillouin zone.