Laser flash photolysis of titanium dioxide suspensions for the evaluation of solvent-mediated radical reactions.

The chemistry originating from the scavenging of the highly electrophilic hole in TiO 2 can be readily monitored using laser flash photolysis techniques. Dilute suspensions are sufficiently transparent in the UV region that long lived signals from reactions of solvent radicals with 1,1-diphenylethylene can be readily monitored. Transient signals originating from hole, electron and trapped radicals are extremely long lived showing stretched exponentials (nanoseconds to milliseconds), adequately described by fractal models.