用遗传算法研究复合团簇（Ag）x（Rh）n—x的基态能和结构

应用遗传算法并结合紧束缚二级矩近似势对复合团簇（Ａｇ）ｘ（Ｒｈ）ｎ－ｘ的基态能和基态结构进行了研究，计算结果显示：随着Ｒｈ原子掺杂比例的增大，复合团簇（Ａｇ）ｘ（Ｒｈ）ｎ－ｘ的基态能量呈现上升趋势，并且其基态结构都是二十面体基础上的微扰。

ENERGIES OF GROUND STATES AND STRUCTURES OF (Ag)_x(Rh)_(n-x) CLUSTERS STUDIED BY A GENETIC ALGORITHM

The tight binding second moment approximation has been employed, in combination with a genetic algorithm, to determine the ground state atomic configrations of Ag x Rh n-x ( n =13,55) clusters for all concentrations x . It is found that the lowest energy structures of both the bimetallic and the pure ( x=0,n ) clusters are slightly distorted with respect to the perfect icosahedron, and the cohesive energies of the ground states increase with increasing the component of Rh. In general, there is a tendency for Ag atoms to be segregated at the surfaces of the bimetallic clusters. At the surfaces of the Ag x Rh 13-x clusters, the Ag atoms and the Rh atoms are separated, and the clusters don't exhibit any ordering. However, at the surfaces of the Ag x Rh 55- x clusters, the Ag atoms and the Rh atoms occupy the positions with high symmetry, and the clusters exhibit ordering.