摘要
The ground-state configurations of the Nbn （n = 2-11） clusters are studied through the first-principles calculations. It is found that niobium clusters （n = 2-11） tend to form compact structures with low symmetry. The clusters with 4, 8 and 10 atoms axe found to be magic and have relatively large highest occupied-lowest unoccupied molecular orbital （HOMO-LUMO） gaps. The Nbn clusters possess low magnetic moments, which exhibit an odd-even oscillational character. The analyses of calculated electronic density and population of the lowest-energy niobium clusters for n =2, 3, 5, 7, 9, 11 show that the total magnetic moments of Nbn originate mainly from a few Nb atoms with longer spacings between them in most cases, while they are located on two Nb atoms for n = 2, 3, 5. The total magnetic moments come mainly from the 4d local moments but with the exception of the Nb5 cluster.
The ground-state configurations of the Nbn （n = 2-11） clusters are studied through the first-principles calculations. It is found that niobium clusters （n = 2-11） tend to form compact structures with low symmetry. The clusters with 4, 8 and 10 atoms axe found to be magic and have relatively large highest occupied-lowest unoccupied molecular orbital （HOMO-LUMO） gaps. The Nbn clusters possess low magnetic moments, which exhibit an odd-even oscillational character. The analyses of calculated electronic density and population of the lowest-energy niobium clusters for n =2, 3, 5, 7, 9, 11 show that the total magnetic moments of Nbn originate mainly from a few Nb atoms with longer spacings between them in most cases, while they are located on two Nb atoms for n = 2, 3, 5. The total magnetic moments come mainly from the 4d local moments but with the exception of the Nb5 cluster.
基金
Project supported by the Program for Science & Technology Innovation Talents in Universities of Henan Province, China (Grant No 2009HASTIT003)
the Natural Science Foundation of Henan University, China (Grant Nos 07ZRZD005 and 07YBZR046)
the Foundation of Science and Technology Department of Henan Province, China (Grant No 082300410010)
