Mainz 2017 – scientific programme

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MO: Fachverband Molekülphysik

MO 13: Probing Vibrations

MO 13.2: Talk

Thursday, March 9, 2017, 11:30–11:45, N 6

Ultrafast dynamics of interfacial water following UV photo-excitation of TiO2 — Saman Hosseinpour, Simon Schlegel, Shumei Sun, and •Ellen Backus — Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz

Hydrogen generation through photo-dissociation of water on the surface of TiO2 has attracted profound attention over the past decades. Nevertheless, the molecular mechanism of the water splitting reaction has remained largely unresolved. The investigation of water during the water splitting reaction requires a surface sensitive tool which can probe the evolution of water molecules at the TiO2 surface upon UV irradiation. In this study we exploit the inherent surface-sensitivity of sum-frequency generation (SFG) spectroscopy to probe the water molecules at the interface between bulk water and TiO2. Femtosecond time-resolved SFG allows us to record changes in the orientation and hydrogen bonding interaction of interfacial water, as a function of the time following a UV pump pulse. Our preliminary results indicated a strong pH dependence of the relaxation/re-orientation of the water molecules after UV-irradiation of the TiO2.