纳米团簇熔化过程的分子动力学模拟

本文采用分子动力学结合嵌入原子多体势,模拟了不同半径的Ni纳米团簇的升温熔化过程,研究团簇尺寸对熔点和表面能的影响.模拟结果表明:团簇的熔点显著低于体材料的熔点.团簇熔化的过程首先是在团簇的表面出现预熔,然后向团簇内部扩展,直到整个团簇完全熔为液态.在模拟的纳米尺度范围内,团簇的熔点与团簇尺寸基本成线性关系.团簇的表面能随着团簇尺寸的增大而减小,而且表面能均高于体材料的表面能.

Molecular dynamics simulations of the melting of nickel nanclusters

The melting process of nickel nanoclusters have been studied by using molecular dynamics simulations with the quantum Sutten-Chen many-body potentials to explore the size effects on the melting point and surface energy of nanoclusters. The present calculations show that the melting temperature of nickel cluster is much lower than that of bulk counterpart. The melting process of nanoclusters starts from the surface layer to the interior, and finally the nanowire becomes entirely a disordered liquid when the temperature reaches the melting point. For the nanometer region we studied, it is evidently linear relation between melting point and reciprocal of diameter. Surface energy of nanocluster decreases with the increasing diameter, and is higher than that of bulk counterpart.