Adsorption and dissociation of water molecules at the alpha-Al2O3(0001) surface: A 2-dimensional hybrid self-consistent charge density functional based tight-binding/molecular mechanics molecular dynamics (2D SCC-DFTB/MM MD) simulation study

摘要

Interfacial adsorption and dissociation of water molecules at the alpha-Al2O3(0001) surface were studied using a novel hybrid 2D-periodic Self-Consistent Charge Density Functional Tight-Binding/Molecular Mechanics Molecular Dynamics (SCC-DFTB/MM MD) simulation strategy. The (0001) surface of alpha-Al2O3 (C-plane) was considered to assess the structural and dynamical behavior of adsorbed water at the interface region. In-plane distribution profiles of oxygen and hydrogen with respect to the non-periodic z-coordinate provide detailed information on the ordering of monolayer adsorbed water molecules at the interface. Dissociation of water molecules occured on the picosecond time scale, indicated by the formation of an additional plane-H peak located at 0.056 nm. Along simulation 4.2 OH groups per nm(2) were formed at the alpha-Al2O3(0001) surface.