Reactions of water molecules in silica-based network glasses.
Given that H(2)O dissolves minimally in quartz, the mechanism for the ubiquitous dissolution of H(2)O in silica glasses has been a long-standing puzzle. We report first-principles calculations in prototype silica glass networks and identify the ring topologies that allow the exothermic dissolution of H(2)O as geminate Si-O-H groups. The topological constraints of these reactions explain both the observed saturation of Si-O-H concentrations and the observed increase in the average Si-Si distance. In addition, calculations of H(2)O and Si-O-H dissociation account for the observed response to radiation by wet thermally grown SiO(2).
Batyrev
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Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA.
Tuttle
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Fleetwood
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Schrimpf
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Tsetseris
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Pantelides
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