Study of Transient Nuclei near Freezing

TL;DR

This study uses molecular dynamics simulations to analyze the relaxation behaviors and transient nuclei near the freezing point in dense hard sphere fluids, revealing distinct regimes and the rapid evolution of cluster sizes.

Contribution

It provides detailed simulation-based insights into the relaxation regimes and cluster dynamics near the fluid-solid phase transition in three-dimensional hard sphere systems.

Findings

Identification of three relaxation regimes: kinetic, molasses, and diffusional decay.

The largest transient cluster at freezing density is only a few sphere diameters and persists for about 30 ps.

Cluster size dramatically increases as the freezing density is approached.

Abstract

The molasses tail in dense hard core fluids is investigated by extensive event-driven molecular dynamics simulation through the orientational autocorrelation functions. Near the fluid-solid phase transition, there exist three regimes in the relaxation of the pair orientational autocorrelation function, namely the kinetic, molasses (stretched exponential), and diffusional power decay. The density dependence of both the molasses and diffusional power regimes are evaluated and the latter compares with theoretical predictions in three dimensions. The largest cluster at the freezing density of only a few sphere diameter in size persist for only about 30 picoseconds (~ 2.8 x 10^{-11}[s]). The most striking observation through the bond orientatinal order parameter is the dramatic increase of the cluster size as the freezing density is approached.