Dynamics of homogeneous nucleation

TL;DR

This paper investigates the dynamics of homogeneous nucleation, revealing that small cold clusters initiate nucleation and that cluster temperature fluctuations play a key role, challenging classical theories.

Contribution

It introduces molecular dynamics insights showing nucleation begins with cold clusters and highlights the importance of temperature fluctuations and non-monotonic cluster growth.

Findings

Cold clusters initiate nucleation.

Cluster temperature fluctuates but remains below gas temperature until critical size.

Nucleation involves exponential decline in cluster size, not just monomer addition or removal.

Abstract

The classical nucleation theory for homogeneous nucleation is formulated as a theory for a density fluctuation in a supersaturated gas at a given temperature. But Molecular Dynamics simulations reveal that it is small cold clusters which initiates the nucleation. The temperature in the nucleating clusters fluctuate, but the mean temperature remains below the temperature in the supersaturated gas until they reach the critical nucleation size. The critical nuclei have, however, a temperature equal to the supersaturated gas. The kinetics of homogeneous nucleation is not only caused by a grow or shrink by accretion or evaporation of monomers only, but by an exponentially declining change in cluster size per time step equal to the cluster distribution in the supersaturated gas.