Reflectivity Spectra of Cd$\text{}_{1-x}$Mn$\text{}_{x}$F$\text{}_{2}$ in the 5-35 eV Energy Range

The reflectivity spectra of Cd$\text{}_{1-x}$Mn$\text{}_{x}$F$\text{}_{2}$ crystals, in the 5-35 eV energy range at 300 and 77 K, were investigated. The observed changes in the shape of spectra, caused by increase of the Mn content, are compared with the calculated band structure of pure CdF$\text{}_{2}$ and with the already available results of XPS experiments for these crystals. The increasing concentration of Mn results in the blurring of the reflectivity structures and shifts the energy of direct exciton (as compared to pure CdF$\text{}_{2}$). Qualitative arguments (hybridization of Mn$\text{}^{2+}$ 3d and F$\text{}^{-}$ 2p states) can describe these effects but a quantitative explanation would require a detailed band structure calculation for these compounds.