Shukla Manoj K, Dubey Madan, Leszczynski Jerzy
Computational Centre for Molecular Structure and Interactions, Department of Chemistry, Jackson State University, Jackson, Mississippi 39217, USA.
ACS Nano. 2008 Feb;2(2):227-34. doi: 10.1021/nn700080p.
A theoretical study was performed to understand the structures and properties of C60-gold nanocontacts. In this investigation, C60 was sandwiched between gold clusters. In the studied clusters, the number of Au atoms varied from 2 to 8 on each side of C60. Molecular geometries of the investigated complexes were optimized at the density functional theory level, employing the B3LYP functional. The 6-31G(d) basis set was used for carbon atoms, while the LANL2DZ effective core potential was used for gold atoms. Geometries of all complexes were optimized under C2h symmetry except for the C60-10Au complex, for which C2 symmetry was assumed. Two different configurations, namely eta(2(5)) and eta(2(6)), for the binding of Au clusters with C60 were considered. It was revealed that complexes corresponding to the latter configuration are more stable than those having the former one. Ground-state geometries of the complexes involving odd numbers of gold atoms on each side of C60 were found to be represented by the triplet configuration. The HOMO-LUMO energy gaps of C60-gold complexes were found to be lower than that of isolated C60. The charge transport properties in the studied system are discussed in terms of molecular orbitals and the Fermi level.
进行了一项理论研究以了解C60 - 金纳米接触的结构和性质。在这项研究中，C60夹在金簇之间。在所研究的簇中，C60两侧的金原子数量从2到8不等。采用密度泛函理论水平的B3LYP泛函对所研究配合物的分子几何结构进行了优化。碳原子使用6 - 31G(d)基组，而金原子使用LANL2DZ有效核势。除了假设具有C2对称性的C60 - 10Au配合物外，所有配合物的几何结构都在C2h对称性下进行了优化。考虑了金簇与C60结合的两种不同构型，即η(2(5))和η(2(6))。结果表明，对应于后一种构型的配合物比具有前一种构型的配合物更稳定。发现C60两侧金原子数量为奇数的配合物的基态几何结构由三重态构型表示。发现C60 - 金配合物的HOMO - LUMO能隙低于孤立C60的能隙。根据分子轨道和费米能级讨论了所研究体系中的电荷传输性质。
