THEORETICAL-STUDY OF OPTICAL AND ULTRAVIOLET PHOTOEMISSION SPECTRA OFTIO2 AND VO2 IN RUTILE PHASE

The optical spectra for two light polarizations and the ultraviolet ph otoemission spectra (UPS) of TiO2 and VO2 in rutile phase have been ca lculated ab initio on the base of the self-consistent energy band stru cture. The semirelativistic extended linear augmented plane wave metho d (ELAPW) was employed. In the case of TiO2 the structures in the theo retical reflectivity curves are shifted by 1-1.5 eV to lower energies with respect to their measured positions, which is attributed to stron g quasiparticle effects in this material. The reflectivity spectra of the metallic VO2 are in a good agreement with experiment. The photoele ctron energy distribution curves (EDC's) agree well with experiment fo r both semiconducting TiO2 and metallic VO2.