NaF-AlF_3二元系铝氟四面体团簇结构的拉曼光谱表征与量子化学从头计算  

Characteristic Raman Spectra and Quantum Chemistry ab initio Calculation on Aluminum-Fluorine Tetrahedral Model Clusters of NaF-AlF_3 Binary

作　　者：赵婷[1] 尤静林[1,2,3] 王媛媛[1] 汪磊[1] 马兰[1] 

机构地区：[1]上海大学材料科学与工程学院,上海200072 [2]法国国家科学研究中心高温和辐射研究所,45071 [3]奥尔良大学,奥尔良法国45067

出　　处：《光散射学报》2012年第1期1-7,共7页The Journal of Light Scattering

基　　金：国家自然科学基金重点项目(50932005);面上项目(20973107;40973046);法国LE STUDIUM机构资助

摘　　要：本文构建了一系列NaF-AlF3二元系铝氟四面体团簇结构模型,应用量子化学从头计算方法,采用Restricted Hatree-Fock(RHF)自洽场方法和6-31G(d)基组对结构进行优化,并用相同的方法和基组进行分子振动模式的模拟计算。考虑相邻铝氟四面体的影响,引入四面体应力指数(SIT)的概念分析和讨论该二元系高频区非桥氟对称伸缩振动及中频区桥氟对称弯曲振动模式。研究表明,高频区铝氟四面体非桥氟对称伸缩振动频率与其铝氟四面体的种类(Qi)密切相关,且铝氟四面体非桥氟对称伸缩振动频率的值随SIT值的增大而增大,呈现较好的线性关系。同时,NaF-AlF3二元系团簇结构的中频区桥氟对称弯曲振动频率主要受桥氟角度的影响。并采用高温拉曼仪测定了分子比为NaF:AlF3=1∶2体系的升温拉曼光谱,随着温度的升高NaF:AlF3=1∶2体系的主峰逐渐向低频移动,观察到Q0、Q1、Q2峰位的变化。Quantum chemistry ab initio calculation was applied to optimize a series of alu- minum-fluorine tetrahedral model clusters and calculate their molecular vibrational modes in terms of Restricted Hatree-Fock（RHF） method with the basis sets of 6-31G（d）. Con- sidering the effect of neighboring aluminum-fluorine tetrahedral, SIT （Stress Index of Tetrahedron） was introduced to analyze the A1-Fb- A1 symmetric bending vibrational modes in intermediate wavenumber range and the symmetric stretching vibrational modes of non-bridging fluorine in high wavenumber range. It suggested that the symmetric stretching vibrational wavenumber of non-bridging fluorine depends mainly on the speciesof aluminum-fluorine tetrahedral （Qi） and appears linear relationship with the value of SIT. It was also demonstrated that the A1-Fb-A1 symmetric bending vibrational wave- number is dominated by the A1-Fb-A1 angle. Raman spectra of NaF： A1Fa = 1 ： 2 were determined with the increasing temperature. Various microstructure units including Q0, Q1, and Q2 were observed and the main peaks shift to low-frequency with the increasing temperature.

关 键 词：NaF-AlF3二元系 团簇结构 从头计算 拉曼光谱 

分 类 号：TF821[冶金工程—有色金属冶金]