Reactions of titanium dioxides with water molecules have been studied by matrix isolation infrared and density functional theoretical calculations. In solid argon, titanium dioxide molecules reacted with water to form OTi(OH)(2) molecules spontaneously on annealing. The potential energy surface along the TiO2 + H2O OTi(OH)(2) reaction path was calculated. Although titanium dioxide-water complex was predicted to be stable, this complex was not observed due to low energy barrier and high exothermicity for the hydrolysis reaction. Evidence is also presented for the formation of OTi-OH2 complex.