Structure and magnetism of 3d series (TM)4 clusters
3d系列 (TM)4 团簇的结构和磁性

Based on the first-principle, we optimize all geometric structures of (TM) 4 c lusters, calculate the energy, frequency and magnetism of (TM) 4 clusters by us ing the local spin density approximation(LSDA) and generalized gradient approxim ation(GGA) density functional theory. We confirm the ground-state structures of (TM) 4 clusters, study their magnetism, binding energy and average interatomic distance systematically, and find that in the 3d series (TM) 4 clusters, the l o cal magnetic moment of Mn 4 cluster is the largest, that of the V 4 cluster is the weakest. Except that the Cr 4 cluster in LSDA and GGA shows anti-ferromag netic coupling,and the V 4 cluster in GGA shows also anti-ferromagnetic coupl ing, other clusters all show ferromagnetic coupling.