Thermodynamic stability of nanoparticles based on coordination number

Abstract

A new model based on calculation of the average coordination number has been developed to predict the size-dependent melting point of nanoparticles when the size and shape are also concerned in the model. As is clear, differences in the shape of nanoparticles will result in changes in coordination number in a system, due to differences in the surface structure. The established model can reflect the influences of both size and shape; moreover, this model is free of any adjustable parameters, and is utilized to predict the thermal stability for low-dimensional materials in this work. For simplicity, the nanoparticle shape is taken to be cuboctahedral, and this is proved to be valid. This is because the theoretical predictions are consistent with experimental evidences and the results of molecular dynamic simulation for many nanoparticles of different elements. Moreover, the results also show that nanoparticles' melting thermodynamic functions are dependent on their size and their atomic diameter for a certain shape.