TbSin(n=2-13)团簇的结构、电子及磁学性质

摘要

利用相对论密度泛函理论在广义梯度近似下研究TbSin(n=2-13)团簇的结构、稳定性、电子和磁学性质.对团簇的平均结合能、离解能、电荷转移、最高占据分子轨道(HOMO)和最低未占据分子轨道(LUMO)的能级差、Mulliken电荷分析和磁学性质进行了计算和讨论.TbSin团簇并没有像实验推测的那样在n=10形成嵌入式的结构.我们推断电子亲和势的急剧变化不仅与嵌入式的结构有关,而且与电子的固有稳定性相关.Mulliken电荷分析表明电荷总是从Tb原子转向Si原子.团簇的磁矩主要局域在Tb原子的周围,并且主要由f电子贡献,f电子表现出局域性并且不参与化学成键.TbSi10为例的分波态密度分析表明Tb与Si原子间存在很强的sp轨道杂化.%The geometries,stability,and electronic and magnetic properties of TbSin(n=2-13)clusters were systematically investigated using relativistic density functional theory(DFT)within the generalized gradient approximation.The average binding energies,dissociation energies,charge transfer,the highest occupied molecular orbital and the lowest unoccupied molecular orbital(HOMO-LUMO)gaps,Mulliken populations(MP),and magnetic properties were calculated and were discussed.The TbSin(n=2-13)clusters do not form encapsulated structures at n=10.We conclude that the stability of TbSin is consistent with the encapsulated geometric structure and also with the inherent electronic stabilization.Furthermore,results of the calculated Mulliken populations show that the charge always transfers from Tb to Si.The magnetic moment is largely located on Tb and is mainly populated by f-block electrons.The f electrons are very localized and to a large extent not responsible for chemical bonding.The partial density of states(PDOS)of TbSi10 shows that there is strong sp hybridization between Tb and Si.