Strain is of significance in packing transition, but the key structural information for metal nanoclusters is still limited. Atomic simulations using molecular dynamics (MD) were performed to explore the microscopic details of atomic packing transition in four icosahedral (Ih) Cu_n@Ag_55-n clusters without or with different number of Cu core atoms. Analytical tools were used to demonstrate the packing transition including internal energy per atom, shape factor, pair distribution functions, and atomic stress as well as cross-sectional images. The simulation results showed the differences of strain distribution between the surface and interior regions of these clusters at elevated temperature, which affected the transition temperatures of these four clusters. The increasing temperature resulted in strong tensile strain in the surfaces and Cu/Ag interfaces, which decreased the packing transition from Ih configuration as well as the shape changes.

中文翻译：

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原子模拟得出的Ih Cu _n @Ag _55-n（n = 0，1，13，43 ）团簇的应变诱导堆积转变

应变在堆积过渡中很重要，但是金属纳米团簇的关键结构信息仍然有限。进行了使用分子动力学（MD）的原子模拟，以探索四个二十面体（Ih）Cu _n @Ag _55-n中原子堆积过渡的微观细节。簇没有或具有不同数量的Cu核原子。分析工具被用来证明堆积转变，包括每个原子的内部能量，形状因子，对分布函数，原子应力以及截面图。仿真结果表明，在高温下，这些簇的表面和内部区域之间的应变分布存在差异，这影响了这四个簇的转变温度。温度升高导致在表面和Cu / Ag界面处产生强烈的拉伸应变，从而降低了从Ih构型以及形状变化引起的堆积转变。