SINDO1 STUDY OF PHOTOCATALYTIC FORMATION AND REACTIONS OF OH RADICALSAT ANATASE PARTICLES

Model calculations are performed with the semiempirical MO method SIND O1 to study the photocatalytic primary reactions at anatase particles in aqueous solution. The photochemical formation and migration of hydr oxyl radicals is investigated at the particle surface, leading to the formation of hydrogen peroxide dr peroxide groups. These reactions rep resent the first step of the oxidative part of the photocatalytic deco mposition of water into oxygen and hydrogen. The anatase particles are simulated by (TiO2)(n)(H2O)(m) clusters with structures corresponding to the anatase solid-state structure. With these clusters the photoph ysical properties of the anatase particles and the photoreactions are calculated on the SCF and CI level. The photoreactions are described b y potential curves along selected reaction coordinates.