摘要:
采用密度泛函理论中广义梯度近似对非典型富勒烯C_(22)和过渡金属内掺衍生物M@C_(22)(M=Sc,Ti,V,Cr,Mn,Fe,Co和Ni)的几何结构和电子结构进行计算研究.发现非典型富勒烯C_(22)的基态结构是含有一个四碳环的单重态笼状结构.过渡金属原子的掺入明显提高了体系的稳定性.C-M键既有一定共价性又有一定离子性.磁性、能级图、轨道分布和态密度图分析表明:M原子的3d轨道和碳笼的C原子的原子轨道之间存在较强的轨道杂化.Ti,Cr,Fe和Ni内掺的结构出现磁性完全猝灭现象.Sc和碳笼间是弱反铁磁作用,V,Mn和Co与碳笼间是弱铁磁作用.
Abstract:
The generalized gradient approximation(GGA) based on density functional theory(DFT) is used to analyze the structural and electronic properties of the unclassical endohedral fullerene M@C_(22)(M=Sc,Ti,V,Cr,Mn,Fe,Co and Ni).It is found that the groundstate structure of the unclassical fullerene C_(22)is a spin singlet cage containing one four-membered ring and the doping of transition metal atom can obviously enhance the stability.It is discovered that the C-M bond have both the covalent and the ionic characteristics. The analyses of magnetism,energy levels,orbital wave functions and density of states show the hybridization between the 3d orbital of M atom and the C atomic orbital in C_(22).In addition,Ti,Cr,Fe and Ni atoms become non-magnetic after they have been doped into the C_(22).