title: Reactions and clustering of water with silica surface.
abstract: The interaction between silica surface and water is an important topic in geophysics and materials science, yet little is known about the reaction process. In this study we use first-principles molecular dynamics to simulate the hydrolysis process of silica surface using large cluster models. We find that a single water molecule is stable near the surface but can easily dissociate at three-coordinated silicon atom defect sites in the presence of other water molecules. These extra molecules provide a mechanism for hydrogen transfer from the original water molecule, hence catalyzing the reaction. The two-coordinated silicon atom is inert to the water molecule, and water clusters up to pentamer could be stably adsorbed at this site at room temperature.
authors.affiliation: Laboratory of Physics, Helsinki University of Technology, P.O. Box 1100, Helsinki 02015, Finland. yma@fyslab.hut.fi
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Ma
authors.forename: A S
authors.initials: AS
authors.lastname: Foster
authors.forename: R M
authors.initials: RM
authors.lastname: Nieminen
mesh_terms: D002384:Catalysis; D016000:Cluster Analysis; D003198:Computer Simulation; D006859:Hydrogen / Q000737:chemistry; D006868:Hydrolysis; D008956:Models, Chemical; D012822:Silicon Dioxide / Q000737:chemistry*; D013816:Thermodynamics; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D012822:Silicon Dioxide; D006859:Hydrogen