Reflection spectra of the rare earth oxides CeO2 and Er2O3

Mirror reflection spectra of CeO2 and Er2=3 crystals having different degree of internal 4f-electron shell filling, are investigated. Measurements were conducted at 300 K within 0.03-40 eV light energy interval. Experimental data in the interzonal transition area are compared to electron structure calculations performed for these oxides in other works. Within the area of fundamental light absorption the oxides investigated are alike by optical properties which is connected with anion component common for them. CeO2 oxide is characterized by the fact that a narrow conductivity zone is additionally located in the forbidden zone