第一性原理研究一维SiO_2纳米材料的结构和性质

Calculation of structure and properties of one-dimensional silica nanomaterials based on first-principle

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.

We have studied silica single and double chain based on two-membered ring and nanotubes based on three-membered ring using the density-functional theory at 6-31G（d） level. The average binding energy, electronic structure and vibration frequency were calculated. Our calculations show that the average binding energy and energy gap monotonically change with increasing SiO2 units. Infrared spectrum indicated that the frequency and intensity of radial and tangential vibration shift obviously. Radial vibration frequency shifts to high frequency while tangential vibration frequency shifts to low frequency showing the existence of quantum size effect and anisotropic property of vibration in SiO2 nanomaterial.