Kinetics Of Vapor-Liquid And Vapor-Solid Phase Separation Under Gravity

TL;DR

This study investigates how gravity influences the phase separation kinetics in a Lennard-Jones system, revealing anisotropic domain growth, new length scales, and the validity of Porod's law under gravitational effects through molecular dynamics simulations.

Contribution

It introduces a detailed analysis of gravity's impact on phase separation kinetics, highlighting anisotropic growth laws and the emergence of new length scales in a Lennard-Jones system.

Findings

Gravity causes anisotropic domain growth and destroys isotropy.

A new length scale depends on gravitational field strength.

Porod's law and Superuniversality remain valid in anisotropic conditions.

Abstract

We study the kinetics of vapor-liquid and vapor-solid phase separation of a hydrodynamics preserving three-dimensional one component Lennard Jones system in the presence of external gravitational field using extensive molecular dynamic simulation. A bicontinuous domain structure is formed when the homogeneous system near the critical density is quenched inside the coexistence region. In the absence of gravity, the domain morphology is statistically self-similar and the length scale grows as per the existing laws. However, the presence of gravity destroys the isotropy of the system and affects the scaling laws. We observe an accelerated domain growth in the direction of the field at late time which resembles sedimentation process. Consequently, a new length scale emerges which strongly depends on the field strength. Similar behavior is observed in the direction perpendicular to the applied field, with a different growth rate. Finally, the validity of Porod's law and Superuniversality in such anisotropic systems is verified in terms of two-point equal time order parameter correlation function and static structure factor.