Study of the ground-state structural and energetic properties of Fe_n,Ni_n(n=2～100) clusters by using the simulated quenching method

The ground-state geometries and energies of Fen and Nin(n=2~100)clusters are investigated by using Gupta potential combined with the molecular dynamics simulated annealing method and the simulated quenching method.Our results show that:Similar ground-state geometries hold for the two types of clusters in most cases,and there all exist structural competitions between the Ih-like,Oh-like,D5h-like and mutual nested of IhD5h-like structures in the structural evolution of both types of clusters.Through analyzing the second-order difference energies and the excessive energies,same magicnumber sequence of n=13,19,23,38and 55can be obtained for both types of clusters,and with the exception of Ni26and Fe75clusters which can also be the magic-number clusters;The origin of the magic numbers of both clusters can be explained by analyzing the average coordination numbers and average nearest neighbor distances.The average binding energies of both clusters increase in general with increasing the cluster size,and the speed of energy evolution of Ni clusters is clearly faster than that of Fe clusters which is in accordance with the experimental observations that the evolution of magnetic moments of Ni clusters is evidently faster than that of Fe clusters.