GEOC 89 |
| Jianwei Wang, Andrey G. Kalinichev, and R. James Kirkpatrick. Department of Geology, University of Illinois at Urbana-Champaign, 1301 W. Green St., Urbana, IL 61801 |
| The talc Mg3Si4O10(OH)2 (001) surface is a model for the ideal charge-neutral siloxane surface, and molecular dynamics simulations of water on this surface provide important new insight into the structure and dynamics of water on such surfaces. The results show the talc (001) is highly hydrophobic at ambient conditions, but that the strengths of the interaction increase at higher temperature and pressure. In partially filled slit-like talc nano-pores, the water molecules prefer to form nearly spherical beads. For filled nano-pores, the resulting water structure is strongly dependent on external pressure and temperature. Mg3Si4O10(OH)2·xH2O systems with x=2/3, 1.0 and 2.0 at 750K and 5.5GPa have stable structures proposed for the 10Å phase, which is a potential phase for water storage in subduction zones. For the Mg3Si4O10(OH)2·2H2O system at 300K and 0.5GPa, H-bond interactions among water molecules and the substrate lead to the formation of a highly ordered 2-dimensional ice-like water structure. |
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Interfacial Phenomena: Linking Atomistic and Macroscopic Properties
1:00 PM-5:50 PM, Tuesday, March 30, 2004 Marriott -- Marquis NW, Oral
Division of Geochemistry |