Molecular Dynamics Modelling of Changes for Packing Structures and Atomic Pressure as Well as Thermodynamics Behaviors of Ag Clusters on Heating and Cooling

Abstract

Molecular dynamics simulations are performed to explore the changes in structures and atomic pressure as well as thermodynamic behaviors in Agn (n = 147–923) clusters during heating and cooling processes. The simulation results demonstrate substantial variations in atomic packing configurations, shape factors, pressure distributions, free energy, and entropy values across differently sized Ag clusters. The results also indicate that during the heating process, larger Ag clusters exhibit a premelting phenomenon on their surface. With increasing temperature, the number of atoms under negative pressure in the Ag clusters gradually increases, inducing transformations in atomic packing structures and overall shape. During the cooling process, the number of atoms under positive pressure gradually decreases. When the temperature decreases to room temperature, the Ag147 cluster shows an icosahedral structure, while other Ag clusters exhibit a face‐centered cubic structure. And the number of atoms in Ag clusters significantly influences their thermodynamic behaviors.