Structures, thermal stability, and melting behaviors of bimetallic Cs–Na clusters studied via molecular dynamics simulation

Abstract

Bimetallic nanoclusters have two features not observed in one-component systems: surface segregation and compositional ordering. Molecular dynamics simulations were performed to study the structural and melting behavior of Cs–Na nanoclusters at different compositions. The thermal stability and melting behaviors were simulated by the application of Gupta many-body model to account for the interatomic interaction potential. The results predict a core–shell structure the details of which depend on the composition. Melting temperatures of varying bimetallic composition were estimated based on profiles of potential energy and specific heat capacity. The melting temperature of Cs–Na nanoclusters is lower than that of the bulk state of each metal, and rises as the Na composition increase. The shape evolution of the binary nanostructures is analyzed in terms of temperature evolution of the deformation parameters. It is found that the mechanism of melting of bimetallic Cs–Na clusters highly depends on the Na content.