Time-resolved Raman scattering study of an adsorbed molecule formed by excited state electron transfer into a colloidal TiO(2) particle.

In this paper we investigate the strength of molecular adsorption on the surface necessary for such charge transfer to occur. We employ time-resolved Raman spectroscopy in an aqueous TiO (2) colloid. The ~ 100angstrom diameter TiO(2) particles have surface adsorbed organic molecules (Eosin-Y). One optical pulse at 532 nm excites the organic molecule into an excited electronic state. The excited state ionizes by injecting an electron into the TiO(2) particle. A second optical pulse at 416 nm then generates the resonance Raman spectrum of the oxidized organic ion on the surface.