Effect Of Potential Function Parameters On The Structure Of Alloy Clusters And Optimization Algorithm

Nanoalloy clusters have been widely used in many fields such as biomedicine,nano-apparatus and industrial catalysis due to their excellent properties.As a very popular research at present,experimental trial-and-error method and structural characterization are usually used to understand the performance of clusters,but pure experimental research is time-consuming and costly.Therefore,theoretical research on cluster structure arises at the historic moment,which provides strong support for experiments.Cluster structure obtained by theoretical research as a guide experiment is usually reliable.Algorithm simulation can not only achieve high efficiency,but also effectively save money,which has been widely used in the research of cluster structure.However,there are still two major problems in theoretical research:one is how to find the real global minimum among a large number of local minima and not fall into the trap of local minima;Second,current studies mainly focus on small size clusters,while optimization of large size clusters is very difficult,both success rate and efficiency are very low.In this paper,Gupta potential function and AIOA algorithm are combined to carry out the following studies:1.The multi-body Gupta potential function is used to describe the interaction between atoms in Co-based Ag and Au-doped clusters,and AIOA algorithm is used to conduct geometric optimization to study the stable structures of Co-Ag and Co-Au clusters.The results show that both Co-Ag and Co-Au clusters have core/shell structure.The stratification of Au and Co atoms is obvious,with Au occupying the outer layer and Co atoms located in the inner layer.However,unlike Ag atoms preferentially occupy icosahedral vertices in Co-Ag clusters,Au atoms tend to be distributed to outer layers in a connected way.2.The improved AIOA-IC-ILS algorithm was used to optimize the most stable structure of Cu-Pd clusters under three different parameters.The interatomic forces of Cu-Pd cluster are described based on multi-body Gupta potential function.The results show that the structure of the 38-atom cluster is different with three different parameters.The stable structure types of Cu-Pd clusters with parameter I can be divided into face-centered cubic truncated octahedral structure and partial icosahedral structure.The cluster stability structure of parameter II can be divided into face-centered cubic truncated octahedron structure and hexapled-pie structure.The main configuration of parameter III is amorphous structure.3.An efficient binary cluster optimization method AIOA-IC-LP was proposed by adding the stretching and compression operation（LP）into the kernel based adaptive immune optimization algorithm（AIOA-IC）and combining with binary dynamic lattice point search（BDLS）.The improved algorithm is successfully applied to the optimization of BLJ_5-100clusters,and the results show that the method is effective.On the other hand,the Gupta potential is used to describe the energy of Cu-Au clusters,and the stable structures of some representative 147-atom Cu-Au clusters are studied,and the results are Mackay icosahedral structures.In conclusion,this method can be widely used for global optimization of binary clusters.