Structural correlations in titanium dioxide

Molecular-dynamics simulations were performed, by using a phenomenological potential model, which takes into account steric repulsion due to atomic si zes, screened Coulomb interaction from charge transfer, charge-dipole inter action due to the large electronic polarizability of the anions, and dipole -dipole interaction, in order to investigate the short- and intermediate-or der correlations in the amorphous phase of TiO2. The results are presented for partial and total pair-distribution functions, coordination numbers, pa rtial static structure factors, and density-density, charge-charge, and x-r ay structure factors. Partial structure factors show that correlations at t he length range 3-8 Angstrom are responsible by the first sharp diffraction peak, which is almost absent in the charge-charge structure factor. Bond-a ngle distributions are also determined to analyze the orientational correla tions in the various phases of the system. Our results are compared with ex perimental data inferred from x-ray spectroscopy. [S0163-1829(99)10109-7].