大尺寸核/层Co-Pd合金团簇稳定结构研究

Core-shell structures of large scale Co-Pd alloy clusters

纳米尺度合金团簇具有特殊的光学、电、磁和催化等性质,在基础研究和应用领域吸引了广泛的兴趣.使用多体Gupta势函数描述Co-Pd团簇原子间相互作用,应用基于内核构建的自适应免疫优化算法确定最稳定结构.研究结果显示:98原子Co-Pd团簇结构可分为面心立方结构、Mackay二十面体、双二十面体、由双二十面体面面相连构成的结构和十面体结构.序列参数显示Co原子位于内层,而Pd原子位于外层.原子半径和表面能进一步解释了Co和Pd原子的分布规律.原子数目为147的Co-Pd团簇均为完整二十面体结构.

Due to special optical, electronic, magnetic, and catalytic properties, the nanoscale bimetallic clusters have been widely studied. The many-body Gupta potential was applied to describe the interatomic interaction in Co-Pd bimetallic clusters, and the stable structures were obtained by using adaptive immune optimization algorithm. Results showed that 98-atom Co-Pd clusters were classified into face centered cubic, Mackay icosahedra, double icosahedra, structures composed by double icosahedra, and decahedra. Furthermore, Co atoms tend to be in the inner core, and Pd atoms prefer locating on the surface, which is further explained by the atomic radii and surface energies. Moreover, all 147-atom Co-Pd clusters adopt Macaky icosahedral motifs.