MOLECULAR-DYNAMICS COMPUTER-SIMULATIONS OF SILICA SURFACE-STRUCTURE AND ADSORPTION OF WATER-MOLECULES

Molecular dynamics computer simulations have been used to study the structure of vitreous silica surfaces and adsorption of water molecules onto the silica surface. Results of simulations of bulk vitreous silica using pair potentials and multibody potentials, as well as simulations of the interaction between H4SiO4H2O molecules are presented as the background to the application of these surfaces. The simulations of water adsorption follow the expected trends of dissociation of adsorbed water molecules, silanol formation, siloxane bond rupture, and preferential association of adsorbed water molecules. Visualization of these surface reactions via dynamic graphics enabled observation of the specific mechanisms of adsorption and bond rupture. Most importantly, this visualization indicates the significant complexity involved in this adsortion process. © 1990.