Characterization of Calcium Fluoride Prepared by Chemical Precipitation Method

Calcium fluoride (CaF2) was precipitated using chemical precipitation method. The quantity was divided into three samples. The X-ray diffraction of samples was clear. The peaks were displaced from each other towards the lower diffraction angles. This is due to an expansion of crystal lattice due to an increase in the formation of atom voids in crystalline structure of compound CaF2. The results of absorption were clear. The energy gap for direct transmission is (3.7) eV and for indirect transmission is (2.9 and 3.1) eV. Evidence for the existence of atom voids. From the results of photoluminescence spectrum at excitation with a wavelength of (300) nm for the first and third samples and for second sample with (400) nm, a shift was observed in peaks as a result of change in density of atom voids and their displacement. The fluorescence spectrum also shifts towards longer wavelengths with increasing exposure to X-ray diffraction.