多元金属团簇稳定结构计算模拟研究
发布时间：2019-05-14 17:46
【摘要】：目前,多元金属团簇成为材料科学领域比较热门的研究课题之一,受到广泛的关注。由于团簇势能曲面上局部极小值的数量非常庞大,且构型空间随着体系尺寸呈指数性增长,因此多元团簇的结构优化是相当困难的。本论文的主要工作是多元金属团簇的结构优化。除此之外,还提出了一种AIOA算法的改进算法。以全局优化算法作为理论分析的方法,探究多元合金团簇在结构和性质上存在的规律。论文的主要内容概括如下:1.采用多体势Gupta函数描述团簇金属原子间作用。使用AIOA算法优化了38原子Au-Pd-Pt的最稳定结构。结果显示团簇的结构类型包括Marks十面体、不完整的Mackay二十面体、完整的截角八面体、密堆积面心立方以及无定型结构。序列参数表明Au、Pd、Pt原子具有分层现象。Au原子分散于团簇内壳,Pt原子在团簇表面生长,而Pd原子与Au原子混融。此外,还通过计算团簇的势能量二阶有限差分值Δ2E和ΔGupta值,比较了近邻团簇之间的相对稳定性。2.使用AIOA算法搜索原子达75的M-Pd-Pt(M=Ag、Au)团簇稳定结构。讨论不同类型原子掺杂导致的Pd-Pt结构变化。13原子M-Pd-Pt(M=Ag、Au)团簇中存在二十面体和非二十面体两种构型,并且Au-Pd-Pt中非二十面体数量要比Ag-Pd-Pt中非二十面体数量多。考察了不同类型金属原子的生长模式,发现在Ag-Pd-Pt和Au-Pd-Pt中Pd和Pt原子在团簇结构中的分布比较相似,但是Au原子比Ag原子更容易聚集生长。最后通过Δ2E值比较了相邻团簇之间的稳定性。3.提出了一种改进的AIOA算法,称之为AIOA-BDLS-ILS算法。以二元LJ函数模型测试该算法的效率,发现比BDLS-ILS算法更高效。使用该算法优化34原子Pd-Pt团簇时,找到了12个能量更低的结构。此外,还优化了50及79原子。序列参数显示Pd和Pt原子有明显的分层现象。
[Abstract]:At present, multi-metal clusters have become one of the hot research topics in the field of material science, and have received extensive attention. Because the number of local minimums on cluster potential energy surfaces is very large, and the configuration space increases with the size of the system, it is very difficult to optimize the structure of multivariate clusters. The main work of this paper is the structural optimization of multicomponent metal clusters. In addition, an improved algorithm of AIOA algorithm is proposed. The global optimization algorithm is used as the theoretical analysis method to explore the law of the structure and properties of multicomponent alloy clusters. The main contents of the paper are summarized as follows: 1. The multibody potential Gupta function is used to describe the interaction between cluster metal atoms. The most stable structure of 38 atom Au-Pd-Pt is optimized by AIOA algorithm. The results show that the structural types of clusters include Mark decahedral, incomplete Mackay icosahedral, complete truncated octahedral, dense stacked face centered cubic and amorphous structure. The sequence parameters show that Au,Pd,Pt atoms have delamination phenomenon. Au atoms are dispersed in the inner shell of clusters, Pt atoms grow on the surface of clusters, and Pd atoms are mixed with Au atoms. In addition, by calculating the second order finite difference values 螖 2E and 螖 Gupta of the potential energy of the cluster, the relative stability between the nearest neighbor clusters is compared. 2. The AIOA algorithm is used to search the stable structure of M-Pd-Pt (M 鈮，
本文编号：2476918
[Abstract]:At present, multi-metal clusters have become one of the hot research topics in the field of material science, and have received extensive attention. Because the number of local minimums on cluster potential energy surfaces is very large, and the configuration space increases with the size of the system, it is very difficult to optimize the structure of multivariate clusters. The main work of this paper is the structural optimization of multicomponent metal clusters. In addition, an improved algorithm of AIOA algorithm is proposed. The global optimization algorithm is used as the theoretical analysis method to explore the law of the structure and properties of multicomponent alloy clusters. The main contents of the paper are summarized as follows: 1. The multibody potential Gupta function is used to describe the interaction between cluster metal atoms. The most stable structure of 38 atom Au-Pd-Pt is optimized by AIOA algorithm. The results show that the structural types of clusters include Mark decahedral, incomplete Mackay icosahedral, complete truncated octahedral, dense stacked face centered cubic and amorphous structure. The sequence parameters show that Au,Pd,Pt atoms have delamination phenomenon. Au atoms are dispersed in the inner shell of clusters, Pt atoms grow on the surface of clusters, and Pd atoms are mixed with Au atoms. In addition, by calculating the second order finite difference values 螖 2E and 螖 Gupta of the potential energy of the cluster, the relative stability between the nearest neighbor clusters is compared. 2. The AIOA algorithm is used to search the stable structure of M-Pd-Pt (M 鈮，
本文编号：2476918
本文链接：https://www.wllwen.com/kejilunwen/huaxue/2476918.html
教材专著
