Abstract Pd-Ag bimetallic nanoparticles have been researched among many fields due to their excellent electronic, catalytic and optical properties. It’s of great significance to learn about the corresponding structural characteristics with respect to the shape, the composition and the size from atomic scale. In present work, improved genetic algorithm accompanied by molecular statics simulations is applied to investigate the structural stability of Pd-Ag nanoparticles systematically. Specifically, the atomic arrangements of eight typical shaped Pd-Ag nanoparticles with different compositions and sizes are studied. Indicators based on energetics are used to characterize the structural stability. It has shown that the Pd-Ag nanoparticles with icosahedral shape are the most stable. Besides, the melting behavior of Pd-Ag nanoparticles is explored using molecular dynamics simulations and Lindemann index is employed to indicate the melting point. It is found that the melting points increase as the size increases and the icosahedral shape of Pd-Ag nanoparticles have the highest melting points.

中文翻译：

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基于分子模拟的 Pd-Ag 双金属纳米粒子的结构优化和熔融行为研究

摘要 Pd-Ag双金属纳米粒子由于其优异的电子、催化和光学性能而受到众多领域的研究。从原子尺度上了解其在形状、组成和大小等方面的相应结构特征具有重要意义。在目前的工作中，改进的遗传算法伴随着分子静力学模拟被应用于系统地研究 Pd-Ag 纳米粒子的结构稳定性。具体而言，研究了具有不同成分和尺寸的八种典型形状的 Pd-Ag 纳米粒子的原子排列。基于能量学的指标用于表征结构稳定性。结果表明，具有二十面体形状的 Pd-Ag 纳米粒子是最稳定的。除了，使用分子动力学模拟探索了 Pd-Ag 纳米粒子的熔化行为，并使用林德曼指数来指示熔点。发现熔点随着尺寸的增加而增加，并且Pd-Ag纳米颗粒的二十面体形状具有最高的熔点。