Insights into water freezing from classical nucleation theory.

Water freezing is a crucial physical phenomenon. The process of ice formation, and the estimation of the ice nucleation rate also have important applications. However, until now, the experimental phenomenon of rapid freezing of water in nanoseconds has not been fully explained theoretically, and the physics underlying the experimental phenomenon has still not been revealed. In this work, combining classical nucleation theory with Mie theory, a kinetic model is developed that reproduces for the first time the experimental phenomenon of decreasing transmissivity. The process of ice formation (nucleation, growth and engulfment) has been revealed. In the process of theoretical derivation, the Zel'dovich-Frenkel (ZF) equation is developed, indicating a limit to the phase transition driving force |Δ|/(T) ≤ 1. By analyzing the experimental and simulation results, it is suggested that the change in the transparency of the sample may be caused by the ice/vacuum interface scattering. In addition, during the rapid phase transition, it was found that the phase transition continues to occur even after phase fraction normalization. Finally, the approximate formula between the nucleation rate and sample transparency is given. This formula can predict the change of sample transparency during phase transition and provides a way to measure the nucleation rate. The results presented here give an insight into the phase transition kinetics, and the methodology may also work for the phase transitions of other materials.