Structural and Dielectric Properties of Quartz−Water Interfaces

Abstract

The structure, orientation, and dielectric of water at the quartz|water interface has been examined under different hydration levels using classical molecular dynamics. The properties of 1H2O/10 Å2, 2H2O/10 Å2, 4H2O/10 Å2, and bulk water on quartz have been benchmarked against experimental data. Structurally, the simulations match existing sum-frequency spectroscopy data, which indicate the existence and orientation of both frozen and loosely bound water on the quartz surface. Good agreement has also been found with existing experimental dielectric data for the 1H2O/10 Å2 level of hydration, and a clear difference has been found in the values of εs = 48, ε∥ = 48, and ε⊥ = 40 for the first slice of a bulk-water−solid interface and εs= 30, ε∥= 30, and ε⊥= 10 for that of 1H2O/10 Å2 water coverage. Overall there is a fundamental difference in shielding between a single interface and the 1H2O/10 Å2 level of hydration.