冷却过程中Pd923 团簇的结构转变研究
Structural changes of Pd923 clusters during freezing

本文利用分子动力学模拟方法, 研究了钯团簇在不同冷却条件下形成晶体及非晶的过程. 利用平均原子体积、双体分布函数、键对分析和键序参数方法研究了微观局域结构随温度的变化关系. 研究发现：在50 K/ps冷却过程中，液态Pd923团簇在1000 K发生玻璃化转变，在100 K下形成非晶结构; 而在0.1 K/ps冷却过程中，液态Pd923团簇发生结晶，并最终形成六角密排（hcp）晶体结构。
The structural transitions of Pd923 clusters during the different quenching processes were studied using molecular dynamics simulations. This work gives the structure properties including the variations of pair-correlation function, bond pairs and bond orientational order parameters with temperature in two rapid quenching processes. Our results indicate that the liquid Pd923 is frozen into amorphous structure at 300 K during the cooling rate 50 K/ps. While the liquid Pd923 is transformed to hexagonal close-packed (hcp) phase at the temperature 100 K during the cooling rate 0.1 K/ps.