Using basin-hopping algorithm within the quantum corrected Sutton-Chen (Q-SC) many-body potential, a systematic investigation has been performed for the best chemical ordering structures of 38-atom trimetallic Pd_nPt(32−n)Rh₆ nanoalloys with truncated octahedral (TO) geometry. The atomic mixing degrees of Pd, Pt and Rh atoms were investigated by using order parameter (RA). The results show that demixing is energetically favorable for the investigated structures, where the number of Rh atoms fixed at 6. The only compositions with the number of hetero bonds lower than the homo bonds are Pt32Rh₆, Pd₁Pt31Rh₆, Pd16Pt16Rh₆ and Pd32Rh₆ which make segregation energetically favorable. The surface segregation of Pd atoms is explained by the lower cohesive energy of Pd atoms than Pt and Rh. The segregation of Pd atoms to the surface is also associated with the smaller surface energies compared with Pt and Rh atoms. Due to the comparable cohesive energies of Rh and Pt atoms, a computation occurs for filling the octahedral core between two kinds.

中文翻译：

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TO结构中PdnPt(32−n)Rh6纳米合金的化学排序研究

在量子校正的 Sutton-Chen (Q-SC) 多体势中使用盆地跳跃算法，对 38 原子三金属 Pd 的最佳化学有序结构进行了系统研究_n铂(32-n)具有截断八面体 (TO) 几何形状的Rh _{6纳米合金。}使用有序参数（R一种）。结果表明，分层对于所研究的结构在能量上是有利的，其中 Rh 原子的数量固定为 6。杂键数量低于同质键的唯一成分是 Pt32Rh ₆ , Pd ₁铂31铑₆ ,钯16铂16Rh ₆和 Pd32Rh ₆使分离在能量上有利。Pd 原子的表面偏析可以通过 Pd 原子的内聚能低于 Pt 和 Rh 来解释。与 Pt 和 Rh 原子相比，Pd 原子向表面的偏析也与较小的表面能有关。由于 Rh 和 Pt 原子的内聚能相当，因此需要计算填充两种八面体核心。