Ab Initio Study of Structure and Bonding of Strontium Clusters
Ab Initio Study of Structure and Bonding of Strontium Clusters
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DOI：
10.1021/jp000092e
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发表时间：
2000-05
影响因子：
2.9
通讯作者：
Yixuan Wang;H. Flad;M. Dolg
中科院分区：
文献类型：
--
作者：
Yixuan Wang;H. Flad;M. Dolg
采用标量-相对论能量一致的大实赝势、相应的实极化势、包含g函数的大价基组以及耦合团簇和组态相互作用关联处理，对2 ~ 13个原子的锶团簇进行了高水平量子化学从头计算.平衡结构，结合能，垂直以及绝热电离势和电子亲合势的报告。最多5个原子的团簇的振动频率也已确定。为了以图形方式说明从货车德瓦耳斯到共价相互作用的转变，并说明sp和sd杂化对化学键合的贡献，从Hartree-Fock波函数计算了相关计算中确定的平衡结构的电子局域化函数（ELF）。锶簇的行为与第12族元素以及镱的簇相当不同，即，由于对键合的共价贡献更显著、电离势低得多和带隙更小，所以它们表现出比镱团簇明显更大的内聚能。这些差异可以主要归因于相当大的sp以及sd杂化锶团簇，而只有前者或后者是重要的12族和镱团簇，分别。
Strontium clusters with 2 to 13 atoms have been studied by means of high level quantum chemical ab initio calculations using a scalar-relativistic energy-consistent large-core pseudopotential, a corresponding corepolarization potential, large valence basis sets including up to g functions as well as coupled-cluster and configuration interaction correlation treatments. Equilibrium structures, cohesive energies, vertical as well as adiabatic ionization potentials and electron affinities are reported. Vibrational frequencies for clusters with up to 5 atoms also have been determined. To demonstrate graphically the transition from van der Waals to covalent interactions for increasing cluster size and to comment on the contributions of sp and sd hybridization to chemical bonding, the electron localization function (ELF) has been calculated from the Hartree-Fock wave functions for the equilibrium structures determined in correlated calculations. Strontium clusters behave rather differently from clusters of the group 12 elements as well as ytterbium, i.e., they exhibit significantly larger cohesive energies than ytterbium clusters due to more pronounced covalent contributions to bonding, and much lower ionization potentials and smaller band gaps. These differences can be mainly attributed to the considerable sp as well as sd hybridization in strontium clusters, while only either the former or the latter is important for group 12 and ytterbium clusters, respectively.