硅氧团簇(SiO_2)_nO_2H_4的密度泛函理论研究  

Density Functional Study on Silica Clusters (SiO_2)_nO_2H_4

作　　者：徐灿[1] 朱莉芳[1] 高晨阳[1] 曹娟[1] 

机构地区：[1]兰州大学物理科学与技术学院

出　　处：《物理化学学报》2006年第2期152-155,共4页Acta Physico-Chimica Sinica

基　　金：磁学与磁性材料教育部重点实验室开放课题;兰州大学资助课题

摘　　要：提出硅氧团簇(SiO2)nO2H4的两种新构型:基于笼状结构和环状结构的构型,并与链状构型相比较,用密度泛函理论的B3LYP方法在6-31G(d)基组水平上计算了三种构型n=2～22(n取偶数)的几何结构、平均结合能、能隙以及能量的二次差分.分析计算结果发现,笼状构型不但在n=4和8处存在幻数团簇(实验上已经观察到),而且预测在n=14处也存在类似的幻数团簇;此外,与(SiO2)n团簇不同的是,(SiO2)nO2H4团簇的环状构型的稳定性从n=4开始大于链状构型,意味着水的加成对硅氧团簇的稳定性有着重要的影响.Two new structures of cage （terminal cage） and ring for silica clusters （SiO2）nO2H4 （n=2-22, n is even） are presented and compared with line structure. Geometric structures, average binding energies, energy gaps and second order difference of energy are systematically studied by density function theory （DFT） B3LYP with basis set 6-31G（d）. The results indicate that for cage structures of （SiO2）nO2H4（n=2-22, n is even） magic number clusters exist not only at n=4, 8, but also at n=14, Ring structures of （SiO2）nO2H4 clusters are different from that of （SiO2）n. For the latter they are more stable than line structures from n=11. However, for the former it is from n=4 ring structures begin to be more stable than line structures. It means that the addition of water has an important effect on the stabilities of silica clusters.

关 键 词：团簇 幻数 密度泛函理论 结构 机理 

分 类 号：O613.72[理学—无机化学]