Effective Nucleation Size for Ice Crystallization

Despite the apparent simplicity of water molecules, the
kinetics
of ice nucleation under natural conditions can be surprisingly intricate.
Previous studies have yielded critical nucleation sizes that vary
widely due to differences in experimental and computational approaches.
In our investigation, we employed all-atom molecular dynamics simulations
to explore spontaneously grown and ideal ice nuclei, revealing significant
disparities in their kinetics. Notably, nucleation defects challenge
the applicability of the classical nucleation theory (CNT) to spontaneously
grown ice nuclei. To address this, we propose a generalized nucleation
theory that effectively describes the kinetics of ice crystal nucleation
across diverse conditions. The kinetics of ice nuclei, as characterized
by the “corrected” critical nucleus size, follow a linear
law akin to that assumed by CNT. This generalized nucleation theory
also provides insights for studying the kinetics of other crystalline
materials.