Study of Transient Nuclei near Freezing

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 ($\sim 2.8 \times 10^{-11}$[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.