A computational study of homogeneous liquid–vapor nucleation in the Lennard-Jones fluid
نویسندگان
چکیده
Umbrella sampling Monte Carlo simulations are used to calculate free energy barriers to homogeneous liquid–vapor nucleation in the superheated Lennard-Jones fluid. The calculated free energy barriers decrease with increased superheating and vanish at the spinodal curve. A statistical geometric analysis reveals the existence of two types of voids: Small interstitial cavities, which are present even in the equilibrium liquid, and much larger cavities that develop as the system climbs the nucleation free energy barrier. The geometric analysis also shows that the average cavity size within the superheated liquid is a function of density but not of temperature. The critical nucleus for the liquid–vapor transition is found to be a large system-spanning cavity that grows as the free energy barrier is traversed. The weblike cavity is nonspherical at all superheatings studied here, suggesting a phenomenological picture quite different from that of classical nucleation theory. © 1999 American Institute of Physics. S0021-9606 99 50232-8
منابع مشابه
A random walk through the dynamics of homogeneous vapor-liquid nucleation.
A method of calculating rates of homogeneous vapor-liquid nucleation based on Langevin dynamics of a few relevant degrees of freedom on a free-energy surface is proposed. The surface is obtained here from simulation and from a semi empirical expression. The mass and friction coefficients are derived from atomistic umbrella-sampling molecular-dynamics simulations. The calculated nucleation rate ...
متن کاملVapor-to-droplet transition in a Lennard-Jones fluid: simulation study of nucleation barriers using the ghost field method.
We report a comprehensive Monte Carlo (MC) simulation study of the vapor-to-droplet transition in Lennard-Jones fluid confined to a spherical container with repulsive walls, which is a case study system to investigate homogeneous nucleation. The focus is made on the application of a modified version of the ghost field method (Vishnyakov, A.; Neimark, A. V. J. Chem. Phys. 2003, 119, 9755) to cal...
متن کاملMolecular Dynamics Simulation of Vapor Bubble Nucleation on a Solid Surface
Heterogeneous nucleation of vapor bubbles on a solid surface was simulated by the molecular dynamics method. Liquid argon between parallel solid surfaces was gradually expanded, until a stable vapor bubble was nucleated. Argon liquid was represented by Lennard-Jones molecules and each surface was represented by three layers of harmonic molecules with the constant temperature heat bath model usi...
متن کاملMolecular 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 mixed with 5000 soft-core carrier gas particles. The observed nucleation rate is seven orders of magnitude larger than ...
متن کاملDensity-functional study of homogeneous bubble nucleation in the stretched Lennard-Jones fluid
Density-functional theory is used to study homogeneous bubble nucleation in the stretched Lennard-Jones liquid. We show that the ratio of density-functional to classical nucleation theory free energy barriers should scale with the quantity Dm/Dmspin , the difference in chemical potential between the bulk superheated and the saturated liquid divided by the chemical potential difference between t...
متن کامل