Rotational dynamics of water associated with interfacial dielectric oscillation and its role in crystal growth of ice.

Abstract

The rotational dynamics of water near the ice/water interface and its relation with the crystal growth of ice are investigated by using molecular dynamics simulations. We find that the dipole-moment profiles of water adjacent to interfaces display an oscillation behavior, which is in contrast to the monotonic decay near the free surface for water films. This dielectric oscillation phenomenon is associated with the strong response to hard solid/water interface. It significantly suppresses the dielectric relaxation and slows down the rotational diffusion near the interface compared to bulk water. We propose that the rotational diffusion determines the active degree of growth sites on interfaces, and its slowdown due to the interfacial dielectric oscillation contributes to reducing the growth rate of ice. With this idea, we predict the crystal growth rate of ice based on the modified Wilson-Frenkel model involving rotational dynamics. The theoretical result agrees well with the simulation.