Ge(SiO_2)_n团簇结构和电子性质的密度泛函理论研究  

Density functional theory study on structural and electronic properties of Ge(SiO_2)_n clusters

作　　者：葛桂贤[1] 井群[1] 闫红霞[1] 杨增强[1] 曹海宾[1] 张建军[1] 

机构地区：[1]石河子大学师范学院物理系生态物理重点实验室,新疆832003

出　　处：《原子与分子物理学报》2011年第4期667-675,共9页Journal of Atomic and Molecular Physics

基　　金：石河子大学高层次人才资助基金(RCZX200747)

摘　　要：采用密度泛函理论中的广义梯度近似(GGA)对Ge(SiO_2)_n(n=1～7)团簇的几何构型进行优化,并对能量、频率和电子性质进行了计算.结果表明,Ge(SiO_2)_n的最低能量结构是在(SiO_2)_n端位O原子以及近邻端住O原子的Si原子上吸附一个Ge原子优化得到;随着锗原子数的增加,增加的锗原子易与原来的锗原子形成锗团簇.掺杂锗原子后团簇的能隙比(SiO_2)_n团簇的能隙小,当多个Ge原子掺杂到(SiO_2)_3团簇时,其能隙随着Ge原子个数的增加出现了振荡,Ge_m(SiO_2)_3的能隙从可见光区到近红外光区变化.二阶能量差分、分裂能表明Ge(SiO_2)_2和Ge(SiO_2)_5团簇是稳定的.The geometry, stability, binding energy and electronic properties of （SiO2）n and Ge（SiO2）, clusters （n=1-7） have been investigated by Density functional theory （DFT）. The results show that the lowest energy structures of Ge（SiO2）. are obtained by adding one Ge on the end site of O atom or the Si near end site of O atom in （SiO2）n, and the incoming Ge atoms tend to cluster on the existing Ge cluster, leading to the formation of Ge islands. The chemical activation of Ge（SiO2）n is improved compared with （SiO2）n. When many Ge atoms are doped on the （SiO2）3, the gap of Gem（SiO2）3 appears the alteration between visible light and infrared. The calculated second-order difference of energies and fragmentation energies show that the Ge （SiO2）n clusters with n-=2 or 5 are stable.

关 键 词：(SiO2)n和Ge(SiO2)n团簇 几何结构 电子性质 

分 类 号：O561[理学—原子与分子物理]