Co_n(n=2～10)团簇的结构和磁性

Structure and Magnetism of Co_n(n=2～10)Clusters

采用密度泛函理论中的局域自旋密度近似(LSDA)和广义梯度近似(GGA)对Con(n=2～10)团簇的几何构型进行优化,并对能量、频率和磁性进行了计算,两种方法确定的基态构型完全一致,并从平均键长、平均配位数和对称性对磁性的影响进行了理论探讨.研究表明,Con(n=2～10)基态团簇的磁性在n=2～4时主要受平均键长的影响,在n=5～9时主要受平均配位数的影响,在n=10时受原子间距和平均配位数的相互影响,最终导致与Co8基态团簇具有相同的磁性.基态团簇在Co5和Co9出现了磁性局域最小点.

All geometry structures of Co n (n=2～10)clusters have been optimized,and th e energy,frequence and magnetism of Co n (n=2～10)clusters were calculated using the l ocal spin density approximation and gener-alized gradient approximation of density functional theory.We found th e same ground state structures in the two methods,and discussed theoretically the influence of the average coord ination number,average bond length and symmetry on clusters magnetism.For Co n (n=2～4)clusters,the magnetism of ground states strongly depends on average bond length,for Co n (n=5～9),it strongly depend on average coord ination number,for Co 10 ,the factors of interatomic distance and average coordination number together lead t o the same magnetism as Co 8 clus-ter.Average moments of Co 5 and Co 9 present magnetic magic number.