Optical properties of CeBo3 and CeB3O6 compounds:: first-principles calculations and experimental results

The cerium borates o-CeBO3, m-CeBO3 and CeB3O6 have been shown to be isostructural to their lanthanum derivatives. From diffuse reflectance, electron energy loss spectroscopy (EELS) and band structure calculations, it has been evidenced that a Ce3+ 4f - 5d transition is responsible for weak absorption peaks around 3.5 eV while the O2p-Ce5d charge transfer gives rise to a strong absorption around 7 eV. Starting from self-consistent full potential LAPW calculations, the dielectric tensors of the three compounds were computed and compared to experimental data. It results in a satisfactory fit between the observed and the calculated extinction coefficient k and the index of refraction n. (C) 2003 Elsevier Inc. All rights reserved.