Condensation Under Controlled Cooling: A Simulation Study

TL;DR

This study uses Monte Carlo simulations to analyze how controlled cooling affects particle condensation, cluster formation, and structure in a 2D Lennard-Jones system, revealing critical density and cooling rate effects.

Contribution

It introduces a modified Metropolis algorithm for realistic thermal motion and systematically explores the influence of cooling rate and density on condensation and cluster properties.

Findings

Maximum particle displacement at a specific cooling rate.

Sharp peak in cluster size distribution at low densities.

Formation of a single large cluster above critical density.

Abstract

The formation, growth, structure and cluster size distribution (CSD) properties in a two-dimensional system of particles interacting with Lennard-Jones (LJ) potential under controlled cooling condition have been studied using Monte-Carlo (MC) method considering modified Metropolis algorithm to introduce realistic thermal motion of the particles. The system, initially at relatively higher temperature Ti, undergoes temperature reduction following exponential law with decay constant a to a lower temperature Tf and subsequently reaches equilibrium. The equilibrium phase configuration depends strongly on the number density c of particles and a. The root mean square particle displacement in the final equilibrium phase shows maximum value for a = ac ~ 10-3 for all c. The CSD properties obtained at a = 10-3 shows a sharp peak in the lower cluster size region for low c. The peak shifts towards higher cluster size for lower a. The CSD fits well with a modified Gamma distribution function. All of the particles in the system form a single cluster when c is larger than a critical value cc (~0.5). A compact well-defined ordered structure is obtained for c > cc and a << ac.