Structural variation of anatase (101) under near infrared irradiations monitored by sum-frequency surface phonon spectroscopy.

We probed the anatase (101) surface irradiated by near-infrared and infrared photons in different ambient gases by monitoring the surface lattice phonon mode using sum-frequency spectroscopy. We found that even under the irradiation of such low energy photons, the stability of surface oxygen vacancies, in comparison to sub-surface oxygen vacancies, can increase sensibly. The variation of this surface phonon mode is also in accordance with the photo-induced hydrophilicity of titanium oxide surfaces, which may provide the microscopic insight into this phenomenon. [ABSTRACT FROM AUTHOR]