Molecular dynamics simulation of supersaturated vapor nucleation in slit pore. II. Thermostatted atomic-wall model

Abstract

, "Molecular dynamics simulation of supersaturated vapor nucleation in slit pore. II. Thermostatted atomic-wall model" (2001 Molecular dynamics simulations of nucleation of a supersaturated Lennard-Jones vapor in slit nanopores are carried out. In this study we extend a previous work ͓K. Yasuoka, G. T. Gao, and X. C. Zeng, J. Chem. Phys. 112, 4279 ͑2000͔͒ in that the walls of the slit are treated as actual atomic walls serving as both the confining solid surfaces and a thermostat. The walls are fixed in place in a fcc lattice structure and wall atoms are subjected to a stiff biharmonic potential thereby bounded to lattice sites. The two walls of the slit have an identical surface ͓fcc ͑100͔͒, but different strength of attractive interaction with the vapor particles-one is strongly adsorbing and another is weakly adsorbing. Heterogeneous nucleation of the supersaturated vapor in the slit is investigated and events of nucleus formation are monitored in real time. A comparison with the previous simulation ͑using rigid structureless walls͒ leads to useful insight into the influence of the wall model to the nucleus formation. In particular, it is found that although the adsorbed particles on the structureless wall diffuse faster than those on the atomic wall, the rate of nucleus formation on the structureless wall is actually about one order of magnitude lower. A detailed analysis of particle and cluster-formation flux indicates that the rate of nucleus formation on the wall is more sensitive to the kinetics of adsorption of gas particles onto the wall than the diffusion rate of adsorbed particles. The higher flux of cluster formation on the atomic wall is apparently due to the higher rate of deposition of monomers onto the wall.

Molecular Dynamics Simulation of Heterogeneous Nucleation and Growth of Argon at Polyethylene Films

“…Kholmurodov et al 12 studied the condensation of a vapor confined in a slit pore by means of molecular dynamics simulations of argon between atomic walls separated by a short distance. This is a special case of heterogeneous nucleation being different from the nucleation at a free surface.…”

Liquid Phase Stability Under an Extreme Temperature Gradient

“…For example, in a hydrophilic nanopore, it is found that a vapor can condense into a liquid at a temperature higher than the saturation temperature [2]. Both experimental and theoretical studies reveal that the shift of phase coexistence curves in confined fluids arises from the presence of wall-liquid interfaces and the associated surface tension [3][4][5][6][7][8][9].…”

Computer Simulations of Adsorption Characteristics of Carbon Dioxide in Slit Graphite Pores

“…Therefore, investigations on the adsorption of carbon dioxide are of great importance. It is commonly recognized that the theoretical methods of density functional theory (DFT) (Peterson et al, 1985;Tan and Gubbins, 1992;Chmiel et al, 1994;Jiang et al, 1994;Zhang and Wang, 2002), Monte Carlo (MC) simulation, especially grand canonical ensemble Monte Carlo simulation (Suzuki et al, 1999;Kanda et al, 2000;Ohkubo et al, 2002), and molecular dynamics (MD) simulation (Cracknell et al, 1995;Matties and Hentschke, 1996a, b;Yasuoka et al, 2000;Kholmurodov et al, 2001;Webb and Grest, 2002) are important and effective tools to study the thermodynamic and transport properties of confi ned fl uids.…”