Ge(SiO2)n团簇结构和电子性质的密度泛函理论研究

采用密度泛函理论中的广义梯度近似(GGA)对Ge(SiO2)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(SiO2)n的最低能量结构是在(SiO2)n端位O原子以及近邻端位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(SiO2)n团簇的能隙小，当多个Ge原子掺杂到(SiO2)3团簇时，其能隙随着Ge原子个数的增加出现了振荡，Gem(SiO2)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(SiO2)2和Ge(SiO2)5团簇是稳定的。

Density functional theory study on structural and electronic

The geometry, stability, binding energy and electronic properties of (SiO2)n and Ge(SiO2)n clusters (n=2-7) have been investigated by The geometry, stability, binding energy and electronic properties of (SiO2)n and Ge(SiO2)n clusters (n=1-7) have been investigated by Density functional theory (DFT). The results show that the lowest energy structures of Ge(SiO2)n 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.