The data in Figures ) and (d) are quite different from experimental results that showed a constant apparent reaction order of 2~3 over the range of 0.27~57.9 mW•cm -2 . However, in the calculations far fewer holes are present in the TiO2 bulk during the water oxidation reaction than are observed experimentally and the apparent high order rate dependence occurs at much lower light intensities. This raises the question of whether the physical properties of the samples studied in the experiments have a very different influence on the chemistry as well as the overall hole populations compared to perfect crystals.