Optical Properties of Calcite in the Vacuum Ultraviolet

Abstract

The reflection spectra of calcite single crystal have been measured in the region 5-12 eV with polarized light normally incident upon the cleaved surface (10\bar11). The principal dielectric constants are determined from the spectra using Fresnel's equation as well as the Kramers-Kronig relation. For the ordinary ray, a strong absorption band is found around 8 eV in the e 2 spectrum, whereas almost no absorption below 9 eV for the extraordinary ray. From the temperature dependence of the spectra this dichroic absorption band is attributed to the intramolecular dipole transition A 1 '→ E ' in the planar CO 3 - radical. It is concluded that the high birefringence in the transparent region (<6 eV) is almost due to the strong dichroic absorption band at 8 eV.