运用密度泛函理论,在631G(d)基组水平上,对二元环组成的SiO2单链、双链纳米线和三元环组成的纳米管进行几何优化,并对其结合能、电子结构和振动频率进行计算.结果表明,平均结合能和能隙均随着SiO2单元的增加单调变化.红外光谱的分析发现,径向和切向的振动频率与强度随着长度的变化有明显的移动.径向的振动频率向高频端移动,而切向的振动频率则向低频端移动,即SiO2纳米材料中存在量子尺寸效应和各向异性现象. The density functional theory (DFT) was used to optimize the geometry of nanotubes composed of binary single-stranded, double-stranded nanowires and ternary rings of binary rings at 631G (d) basis set level. The binding energies, electronic structures And vibration frequency were calculated.The results show that the average binding energy and energy gap monotonically change with the increase of SiO2 unit.The analysis of the infrared spectrum shows that the radial and tangential vibration frequency and intensity have a significant shift with the length The radial vibration frequency moves to the high frequency side, while the tangential vibration frequency moves to the low frequency side, that is, the quantum size effect and anisotropy in the SiO2 nanomaterials.