Poster: Molecular Dynamics Simulations of Water in Confined Surfaces.

The freeze-thaw cycles of water in confined media, such as in porous soil is necessary for proper infrastructure development in cold regions experiencing large variations in temperature as a result of climate change. In this project we use the TIP4P/2005 model of water in the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) to try and uncover some poorly understood qualities of confined water. The four site TIP4P/2005 model was chosen over other water models, and even over other four site models, since it gave the most accurate results for density over other models for hexagonal ice. This model includes sites for two hydrogen atoms, one oxygen atom, and a virtual "m" atom between the two hydrogen atoms. Previous literature shows that when liquid-ice boundaries are coexisting with solid surfaces there is a solidification effect on the water molecules even with minimal or no change in temperature or pressure. The Tersoff potential was used to simulate the interactions between the SiO2 wall atoms. We ran simulations of both alpha-quartz crystalline silica as well as annealed amorphous glass silica and compare the ice crystallinity, interface RDF, and atomic density in the Z-direction at varying cooling rates. These results will allow us to understand the fundamental principles of ice formation in confined systems.