Si_4X(X=C,N,O,F,Si,P,S,Cl)结构和稳定性的理论研究  

Theoretical Study of the Geometry and Stability of Clusters Si_4X(X=C, N, O, F, Si, P, S,Cl)

作　　者：孙仁安[1] 张旭[1] 李钠[1] 

机构地区：[1]辽宁师范大学化学系,辽宁大连116029

出　　处：《辽宁师范大学学报（自然科学版）》2003年第3期275-279,共5页Journal of Liaoning Normal University:Natural Science Edition

基　　金：辽宁省教育厅资助项目(990321076)

摘　　要：利用Gussian 98程序,B3LYP方法,在6 311G 水平上对Si4X(X=C,N,O,F,Si,P,S,Cl)原子簇的几何构型进行优化和频率计算,得出各原子簇的稳定结构.结果表明,Si5原子簇的最稳定构型具有D3h对称性.用杂原子X(X=C,N,O,F,P,S,Cl)取代Si5原子簇中的Si原子,几乎都得到C3V和C2V对称的稳定构型(Si4F原子簇只有C2V对称的稳定构型,Si4Cl原子簇不存在这两种稳定构型).对具有相同对称性的杂原子簇中Si—X键长变化规律进行研究,发现同一周期从左到右,Si—X键长与其对应的原子共价半径和相比较,其键长变化率逐渐增大.杂原子的加入对原Si5原子簇中的其它Si—Si键长影响不大.The geometries of Si4X(X=C, N, O, F, Si, P, S, Cl) clusters are optimized with Density Function Theory B3LYP under the level of 6-311G* basis set, and their stable geometries are obtained. It is found that the cluster with D3h symmetry type of Si5 cluster is the most stable structure and the doped clusters Si4X(X=C, N, O, F, P, S, Cl) almost have the structure with the C3V and C2V symmetry type when Si atom of the cluster Si5is substituted by an atom X(X=C, N, O, F, P, S, Cl) (the Si4F cluster has only C2V symmetry structure, but the Si4Cl cluster has none). Furthermore, we have analyzed the Si-X the variety ratio of bond length of the structures which have the same symmetry type. It is found that the Si-X bond length variety ratio becomes augment in turn compared with the sum of the two atomic valence bond length from left to right in the same period. The influence of the atoms adulteration is not strong for the Si-Si bond length of the Si5 cluster.

关 键 词：原子簇化学 几何构型 稳定性 稳定构型 键长变化规律 密度泛函方法 频率计算 硅原子簇 

分 类 号：O613.72[理学—无机化学] O641.121[理学—化学]