The ground-state geometries and melting behaviors of Co_nCu_(38-n) (n=0~38) clusters

Based on the Gupta many-body potential the ground-state geometries and melting properties of Con Cu(38-n)(n=0~38)clusters are investigated systematically by using the genetic algorithm and molecular dynamics simulation combined with the quenching method.Our results show that except for Co7Cu31which prefers to the Ih-like structure as the ground-state,all other bimetallic clusters are similar to that of the pure Cu38(Co38)cluster with the Oh-like structure as the ground-state,and the central site is superior to surface ones for replacing the Co atom(s)of the Con Cu(38-n)(n=0~38)clusters with increasing the Co atoms;From analyzing the second-order difference energy and the mixing energy,Co7Cu31and Co14Cu24are found to be the magic number clusters;There are abnormal melting behavior without obvious wide peaks in heat capacity curves for all these 38-atom clusters and which are characterized through analyzing the atomic equivalence indexes and the distribution of potential energies of quenching structures,and the influence to the melting behaviors is addressed to the competition between two dynamical structures(Oh-like and Ih-like)in the process of cluster melting.