2001 Volume 15 Issue 1 Pages 39-46
A heterogeneous nucleation of liquid droplets on a solid surface from vapor and a heterogeneous nucleation of vapor bubbles on a solid surface from liquid were simulated by the molecular dynamics method. Argon liquid or vapor was represented by Lennard-Jones molecules and a solid surface was represented by harmonic molecules with the constant temperature heat bath model using the phantom molecules outside of harmonic molecules. Nucleation of liquid droplet was realized by suddenly cooling a solid surface in contact with dense argon vapor. From the number distribution of clusters appeared on solid surface, heterogeneous nucleation rate and free energy of clusters dependent on the cluster size were measured. On the other hand, liquid argon between parallel solid surfaces was expanded in order to simulate the vapor bubble nucleation on the solid surface. With visualizations of the void patterns, molecular-level nucleation dynamics were explored for slowly and rapidly expanding systems. For both systems, the heterogeneous nucleation rate and the critical radius were not far from the prediction of the classical theory.
