Si3Xn (X=C,O,N;n=1,2)团簇的密度泛函研究

使用密度泛函理论(DFT)的杂化密度泛函B3LYP方法在6-31G*基组水平上对Si3Xn(X=C,O,N;n=1,2)团簇各种可能的构型进行几何结构优化,预测了各团簇的最稳定结构.并对最稳定结构的电子结构、振动特性、成键特性和电荷特性等进行了理论研究.结果表明团簇的几何结构都是平面结构,通常Si3X2出现是Si-X键,较少出现X-X键;而Si3X中出现Si-X键和Si-Si键共存,Si3Xn(X=C,O,N;n=1,2)团簇的电荷布局分布表明这种电荷转移的作用使得团簇中所有X原子呈负电性,Si原子显正电性.处于不同位置的Si原子呈不同大小布局数,而且由于Si3X2的对称性,2个X负电性相同.

Density functional theory study of Si3Xn(X=C,O,N;n=1,2) clusters

Possible geometrical structures and relative stability of Si3Xn(X=C,O,N;n=1,2) clusters are studied by using the hybrid density functional theory (B3LYP) with 6-31G*basis sets in this article. For the stablest isomers of Si3Xn(X=C,O,N;n=1,2) clusters, the electronic structure, vibrational properties, bond properties and charge properties are analyzed. The calculated results show that, all optimized Si3Xn(X=C,O,N;n=1,2) clusters are planar structure. Usually the Si-X bond is coexisted in the cluster of Si3X2, but the X-X bond is infrequent in it. Meantime the Si-X bond and Si-Si bond is coexisted in the cluster of Si3X. The natural charge of atom of Si3Xn(X=C,O,N;n=1,2) clusters suggest that all X atoms are negative because of the charge transfer, meantime all Si atoms are positive. The natural charge of Si atom is different in different location, but the two X atoms are same for the Symmetry of Si3X2