Geometric and electronic properties of endohedral Si @ C74.
Geometric and electronic properties of endohedral Si @ C74.
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DOI：
10.1063/1.2339022
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发表时间：
2006-09
期刊：
影响因子：
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通讯作者：
Chunmei Tang;Yongbo Yuan;K. Deng;Yuzhen Liu;Xiang-yin Li;Jinlong Yang;Xin Wang
中科院分区：
文献类型：
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作者：
Chunmei Tang;Yongbo Yuan;K. Deng;Yuzhen Liu;Xiang-yin Li;Jinlong Yang;Xin Wang
采用基于密度泛函理论的广义梯度近似方法对Si @ C（74）的几何和电子性质进行了理论分析。发现Si @ C（74）的五种可能的优化构型中，Si原子最有利的内配位在sigma（h）平面上的五边形环中心之下，即，Si @ C（74）-5，它不同于半经验分子轨道计算和分子力学计算所计算的Si在C（74）中的中心稳定位，也不同于稳定位，即，对于金属原子Ba、Ca和Eu，在C（74）中的σ（h）平面上沿C（2）轴的沿着[6，6]键下。sigma（h）平面上的变形电荷密度表明Si @ C（74）-5中的Si-C键具有共价特征，而Mulliken电荷分析以及较长的Si-C键长表明Si @ C（74）-5中的Si-C键具有离子特征。因此，我们推测Si @ C（74）-5中的Si-C键同时具有共价键和离子键的特征。
The generalized gradient approximation based on density functional theory is used to analyze the geometric and electronic properties of Si @ C(74). It is found that among the five possible optimized geometries of Si @ C(74), the most favorable endohedral site of Si atom is under the center of a pentagon ring on the sigma(h) plane, i.e., Si @ C(74)-5, which is different from the center stable site for Si in C(74) calculated by the semiempirical molecular orbital calculations and molecular mechanics calculations, and it is also different from the stable site, i.e., under a [6, 6] bond along the C(2) axis on the sigma(h) plane in C(74) for metal atoms Ba, Ca, and Eu. The deformation charge density on the sigma(h) plane reveals that the Si-C bonds in Si @ C(74)-5 have covalent character, while the Mulliken charge analysis together with a longer Si-C bond length reveals that the Si-C bonds in Si @ C(74)-5 have ionic character. Therefore, we infer that Si-C bonds in Si @ C(74)-5 contain both covalent and ionic characters.