  We investigate band gaps, equilibrium structures, and phase stabilities of
several bulk polymorphs of wide-gap oxide semiconductors ZnO, TiO2,ZrO2, and
WO3. We are particularly concerned with assessing the performance of hybrid
functionals built with the fraction of Hartree-Fock exact exchange obtained
from the computed electronic dielectric constant of the material. We provide
comparison with more standard density-functional theory and GW methods. We
finally analyze the chemical reduction of TiO2 into Ti2O3, involving a change
in oxide stoichiometry. We show that the dielectric-dependent hybrid functional
is generally good at reproducing both ground-state (lattice constants, phase
stability sequences, and reaction energies) and excited-state (photoemission
gaps) properties within a single, fully ab initio framework.
