Title: COMPUTER SIMULATION STUDY OF THE DIFFUSION OF WATER MOLECULES CONFINED IN SILICA GEL
Authors: T.Patsahan, M.Holovko (Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine)

The molecular dynamics simulations are used to study the dynamic properties of SPC/E water molecules confined in silica gel. The model proposed in this study covers three main features that characterize systems of that kind: the excluded volume due to the substrate presence, strong attraction between pore surface and water molecules, randomness of confinement structure. The gel-like structure is modelled as an array of si\-li\-ca composite spheres that are randomly dispersed in volume. Therefore, the spherical SiO$_2$ composite bearing silanol groups on the surface is designed as an element of the porous medium of silica gel. The diffusion coefficients of water molecules are calculated at different temperatures and water densities. To illustrate the model proposed and the behavior of molecules near the pore surface, several snapshots are presented.

Key words: molecular dynamics, water, confinement, silica gel, diffusion
PACS: 02.70.Ns, 68.43.Jk, 82.70.Gg