Resonant Two-photon Oxidation in Vanadium Oxyhydrate Nanowires Above a Threshold Laser Intensity
The present work discloses the unusual photooxidation observed for V 3O 7•H 2O nanowires under 514 nm excitation above a threshold intensity of 0.30 kW/cm 2. We explicate this phenomenon by in-situ Raman and photoluminescence spectroscopy at varying laser intensities as well as models for the transformation kinetics and energy band structure associated with H 2OVO 5 octahedron. The photooxidation is found to be triggered by two-photon cleavage of the H 2O-V bond through excitation via nonbonding d-states. Subsequently, V 3O 7 spontaneously oxidizes to V 2O 5. However, the competing process of H 2O's rebonding is also realized. Hence, transformation to V 2O 5 occurs only if the H 2O-V bond-cleavage rate exceeds a threshold, pushing the number of concomitantly broken bonds in the smallest structural unit to a critical number. © 2012 American Chemical Society.
Ç. Ö. Topal et al., "Resonant Two-photon Oxidation in Vanadium Oxyhydrate Nanowires Above a Threshold Laser Intensity," Journal of Physical Chemistry C, American Chemical Society (ACS), Jan 2012.
The definitive version is available at http://dx.doi.org/10.1021/jp2108494
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