A molecular dynamics study on cooling rate effect on atomic structure of solidified silver nanoparticles

Abstract

The atomic structures and solidification point of silver nanoparticles (SNPs) are studied in a series of molecular dynamics simulations based on the empirical embedded atom methods (EAM). The solidification point is calculated from the extracted potential energy during the cooling process, whereas the atomic structures are analyzed using the common neighbor (CN) method. The results indicate that the structures of the solidified SNPs are very sensitive to both the applied cooling rate and the particle size. We find the critical cooling rate where a glassy structure is observed. Below the critical rate, polycrystalline nanoparticles are formed, where the percentage of the close-packed structures, i.e., FCC and HCP, decreases with increasing cooling rate. Moreover, the proportion of those structures is always larger with a bigger particle size for an identical applied cooling rate. The findings in this study provide useful information for many practical applications where the nanostructure strongly affects thermal management and operational efficiency.