Structural Optimization Of Cobalt Based Alloy Clusters Doped With Noble Metal Atoms

Due to the unique properties of the alloy clusters,they are of great interest in the current scientific field,especially in the catalysis of biology and chemistry.In the process of optimizing the optimal structure,in order to determine its stable structure,the description of the potential energy function of alloy clusters plays a key role.The main contents of this paper are summarized as following:1.The most stable structure of Co₅₅Ag_nand Co₅₅Au_n?n=1-55,60,70,80,92?clusters was determined by the kernel based adaptive immune optimization algorithm?AIOA?and described by the multi-body Gupta potential function.The results show that Mackay icosahedron is the most stable configuration of Co₅₅Ag_nand Co₅₅Au_n?n=1-55,60?.Compared with Co-Ag clusters,Co-Au clusters have more icosahedron structures.In addition,according to the analysis of sequence parameters,it is found that Co atoms are located in the inner layer,while Ag and Au atoms are located in the outer layer,showing a nuclear layer structure.The distribution of Ag and Au on the surface is mainly determined by atomic radius and surface energy.The stable structure of Co₅₅Ag₉₂2 with 147 atoms is amorphous,while Co₅₅Au₉₂2 has a complete icosahedral structure.2.The global stable structure of Co-Pd and Co-Pt clusters is optimized by using the kernel based adaptive immune optimization algorithm?AIOA-IC?.For 98 atom Co-Pd clusters,they have face centered cubic structure,Mackay icosahedron,biicosahedron,and decahedron structure.The sequence parameters show that the Co atom is in the inner layer,while the Pd atom is in the outer layer.The atomic radius and surface energy further explain the distribution of Co and Pd atoms.The Co-Pd clusters of 147 atoms are all complete icosahedral structure.For 98 atom Co-Pt clusters,the interatomic interaction is described by the multi body Gupta potential.These clusters can be divided into six types:face centered cubic,stacked staggered,decahedral,icosahedral,Leary tetrahedral and amorphous.The results show that in the co poor region,the ComPt98-m cluster adopts Fcc and Sf Fcc configurations,while in the Co rich region,it is mainly icosahedron.It is found that the LT motif is the most stable for most of the compositions,and the Co₈₀Pt₁₈8 cluster shows a T_d point group.The construction of T_d LT starts with regular tetrahedron.In addition,atom distribution and high energy analysis show that the studied Co-Pt clusters tend to have a good mixing mode,and at Co₅₅Pt₄₃,the mixing degree between Co and Pt atoms is the highest,which is an amorphous motif rather than a lt motif.The rearrangement of atoms caused by energy competition between different geometric structures is analyzed.3.Genetic algorithm is used to search the most stable structures of Lennard-Jones clusters,Cu and Au clusters based on Gupta potential function and binary Lennard-Jones clusters.The new software takes the parameters of algorithm operation as the input variables,and makes readers use the method better through the display of graphical interface.In addition,the matlab program of genetic algorithm for cluster structure optimization is introduced in detail.