(SiO_2)_nO_2H_4的红外振动光谱的理论研究  

Theoretical Study on Infrared Vibration Spectrum of(SiO_2)_nO_2H_4

作　　者：曹娟[1] 徐灿[1] 朱莉芳[1] 王喜民 

机构地区：[1]兰州大学磁学与磁性材料教育部重点实验室 [2]靖远煤业公司第四中学,甘肃白银730913

出　　处：《光谱学与光谱分析》2007年第9期1715-1718,共4页Spectroscopy and Spectral Analysis

基　　金：磁学与磁性材料教育部重点实验室开放课题;兰州大学留校博士研究启动基金项目资助

摘　　要：运用密度泛函理论,在6-31G(d)基组水平上,计算了纳米尺度的(SiO2)nO2H4链状、环状、笼状三种不同构型的红外振动光谱。对准一维的链状和环状结构,红外振动较强峰的频率随着长度的增加单调变化,显示了较强的尺寸依赖性;沿纳米线(环)轴向和垂直于轴向的振动模式,频率对尺寸的依赖关系相反,揭示了纳米材料的振动性质的各向异性。笼状结构由于构型的复杂性而使得其不具备准一维的特性,同时结构的对称性降低,红外振动模式数目增加。三种构型中二元环和硅羟基的振动以及笼状构型中硅氧四面体骨架的振动与实验上所观测到的振动峰相吻合。红外光谱方面的理论计算结果对实验合成的SiO2纳米材料的表征具有指导意义。Infrared vibration spectra of nanosize（SiO2）nO2H4 with line,ring and cage structures were calculated using the density-functional theory（B3LYP） at 6-31G（d） level.For quasi 1D（one dimension） line and ring structure,the frequencies of stronger infrared vibration modes monotonically change as a function of the length,which shows strong size effect.The IR vibration modes in directions parallel and perpendicular to the axis of nanoline or nanoring have opposite size dependence trends,showing the real vibration anisotropy property of nano scale material.Due to constructional complexity,cage structure does not have quasi 1D character.Morever,IR vibration modes increase as structural symmetry decreases.Vibrations of two-membered ring,isolated hydroxyls of three structures and framework SiO4 tetrahedron in cage structure agree well with experimental data.Theoretical calculation result of IR spectra can be used to guide characterization of silicon oxide nano scale materials fabricated in experiment.

关 键 词：SiO2纳米材料 红外光谱 密度泛函 

分 类 号：O641[理学—物理化学]