On the growth rate of ices: Effect of pressure and ice phase

Ice, the solid phase of water, can adopt a wide range of structures, making it of interest from both fundamental and applied perspectives. In this study, we used molecular dynamics simulations to compute the growth rates of four ice phases: Ih, III, V, and VI. To enable comparisons at the same temperature, different pressures were applied to each phase. Our analysis of pressure effects on the growth rate of ice Ih revealed only a minor influence, allowing us to attribute variations in growth rates primarily to structural differences among ice phases. We observed that ices Ih and VI exhibit similar growth rates, whereas ices III and V grow significantly faster. Rapidly growing ice phases exhibit a high growth efficiency, meaning that less molecular motion is needed to form the solid. We hypothesize that proton ordering may influence ice growth, as partially ordered ice phases (III and V) exhibit faster growth rates than fully disordered phases (Ih and VI). Alternative explanations for ice growth rate trends, such as unit cell complexity or melting entropy, are ruled out. Finally, we assessed the predictive capability of the Wilson–Frenkel theory. While the theory does not inherently account for structural complexity—resulting in similar growth rates across all phases—we found that introducing a phase-specific characteristic length enables it to accurately reproduce our simulation results.