Optical polarized properties related to the oxygen vacancy in the CaMoO4 crystal

The electronic structures, dielectric functions and absorption spectra for the CaMoO4 (CMO) crystal with and without oxygen vacancy VO2+ have been calculated using the CASTEP code with the lattice structure optimized. The calculated results indicate that the optical properties of the CMO crystal show anisotropy and its optical symmetry coincides with the lattice structure geometry of the CMO crystal. The calculated absorption spectra indicate that the perfect CMO crystal does not display absorption band in the visible and near-ultraviolet range. However, in this range, the absorption spectra of the CMO crystal containing VO2+ exhibit one peak at about 1.84 eV (673 nm). It predicates that the 680 nm absorption band is related to the existence of VO2+ in the CMO crystal.