MOLECULAR-DYNAMICS OF HOMOGENEOUS NUCLEATION IN THE VAPOR-PHASE - I -LENNARD-JONES FLUID

Molecular dynamics computer simulation was carried out to investigate the dynamics of vapor phase homogeneous nucleation at the triple point temperature under supersaturation ratio 6.8 for a Lennard-Jones fluid . To control the system temperature, the 5000 target particles were mi xed with 5000 soft-core carrier gas particles. The observed nucleation rate is seven orders. of magnitude larger than prediction of a classi cal nucleation theory. The kinetically defined critical nucleus size, at which the growth and decay rates are balanced, is 30-40, as large a s the thermodynamically defined value of 25.4 estimated with the class ical theory. From the cluster size distribution in the steady state re gion, the free energy of cluster formation is estimated, which diminis hes the difference between the theoretical prediction and the simulati onal result concerning the nucleation rate. (C) 1998 American Institut e of Physics. [S0021-9606(98)50643-5].