Aun+1-1、AunCr-1 (n=1~10)团簇结构、稳定性与电子构型研究

Study on the structures, stabilities, electronic configurations of anion gold clusters and anion Cr-doped gold clusters

摘要:

采用密度泛函理论对阴离子团簇〖"Au" 〗_"n+1" ^"-1" 、AunCr-1 (n=1~10)的基态结构、稳定性、电子构型与磁性做了系统研究.结果表明: 〖"Au" 〗_"n+1" ^"-1" 均为平面构型，AunCr-1 (n=1~6) 为平面结构，AunCr-1 (n=7~10) 为体结构; 〖"Au" 〗_"n+1" ^"-1" 替代掺杂Cr原子提高团簇的稳定性;离解能与二阶差分能结果表明偶数的〖"Au" 〗_"n+1" ^"-1" 、AunCr-1稳定性比相邻奇数团簇高;轨道的有效电荷分布结果说明Cr原子的掺入使得Au原子内部spd杂化变得更复杂，AunCr-1中Cr原子成为价电荷的主要接受者;轨道磁矩分布结果则表明〖"Au" 〗_"n+1" ^"-1" 电子结构随尺寸增长表现为明显的开闭壳层结构，AunCr-1的电子结构均为开壳层, 〖"Au" 〗_"n+1" ^"-1" 的磁矩主要由Au5d轨道贡献, 而AunCr-1的磁矩则主要由Cr 3d轨道贡献.

Abstract:

The ground state structures, stabilities, electronic configurations and magnetic properties of anion gold clusters and anion Cr-doped gold clusters have been systematically investigated by density functional theory. Our results show that 〖"Au" 〗_"n+1" ^"-1" (n=1~10) clusters and AunCr-1 (n=1~6) clusters are planar configurations and AunCr-1 (n=7~10) clusters are body structures. Remarkably, the stabilities of anion gold clusters can be improved by Cr-doping. The dissociation energies and second-order difference energies results indicate that the even number of 〖"Au" 〗_"n+1" ^"-1" clusters and AunCr-1 clusters are more stable than adjacent odd clusters. The charges of the orbitals indicate that the incorporation of Cr atom makes the spd hybridization of Au atoms more complicated, and the Cr atoms are the main acceptors of the valence charge in AunCr-1 clusters. The results of orbital magnetic moment show that the electronic structure of 〖"Au" 〗_"n+1" ^"-1" clusters exhibit obvious open-closed shell structures with size increasing and the electronic structures of AunCr-1 clusters are Open shell. In this regime, the magnetic moment of 〖"Au" 〗_"n+1" ^"-1" clusters is mainly contributed by the Au5d orbitals, while the magnetic moment of AunCr-1 clusters is mainly contributed by Cr3d orbitals.