VACUUM-ULTRAVIOLET REFLECTANCE AND ELECTRON-ENERGY-LOSS SPECTRA OF CATIO3

Normal incidence light reflection measurements have been performed for CaTiO3 single crystals over the wide energy region from 0.4 to 35 eV. The dielectric functions and optical constants are evaluated from the reflectance spectrum by the Kramers-Kronig transformation technique. The experimental electron energy loss spectrum is in reasonable agreem ent with the energy loss function calculated from the dielectric funct ions. In comparison of the dielectric functions with joint density of states, the peaks in the energy region from 3 to 8 eV are mainly attri buted to the transition from O 2p to Ti 3d orbitals, and those from 8 to 15 eV are assigned to the transitions from O 2p to Ti 3d, Ca 4s and Ti 4s orbitals.