SHG observation of rutile TiO2(110)/H2O interface under UV light illumination

We have measured the SH intensity from the TiO2(110)/H2O interface under UV-light illumination as a function of the azimuthal angle of sample rotation about the surface normal. The SII intensify increases during UV-light illumination and then decreases in the dark. The SH intensity pattern as a function of the azimuthal angle remains unchanged during this change in absolute SH intensity. We suggest that some interaction between the UV generated surface defects and the interface Ti-O-Ti-O- chain enhances the optical transition in the chain without modifying the shapes of the wavefunctions. (C) 1999 Published by Elsevier Science B.V. All rights reserved.