基于密度泛函理论的SF6分解特征组分激光拉曼特征频谱研究

Study on Laser Raman Spectra of SF Decomposed Characteristic Products Based on Density Functional Theory

六氟化硫(SF6)分解特征组分检测是判断气体绝缘设备早期潜伏性故障较有效的方法之一,通过监测分解特征组分的类型和浓度能够有效评估电气设备的运行状态,从而避免绝缘突发性事故。拉曼频谱分析技术可实现单一波长激光对气体样品进行无损检测,对SF6分解特征组分检测具有优异的适用性和高效性。针对4种SF6分解典型特征组分,以密度泛函理论(DFT)中的B3LYP方法建立了气体分子模型,采用6-311G(2df,p)基组对分子模型进行优化和拉曼频移特征仿真。同时,基于搭建的拉曼光谱实验平台,对相同含量的4种特征组分实现拉曼特征频谱检测。仿真结果表明密度泛函计算值和实测值与NIST标准值间具有良好的相关性,计算值中CF_(4)、CO、H_(2)S、SO_(2)的特征峰分别为908.97、2 221.11、2 688.82、1 175.24 cm^(-1),为用拉曼光谱实现SF6分解特征组分的定性和定量分析奠定了基础。

Sulfur hexafluoride(SF6) decomposition characteristic component detection is one of the most effective methods to judge the early latent fault of gas insulated equipment. The operation status of electrical equipment can be effectively evaluated by monitoring the type and concentration of decomposition characteristic components,so as to avoid insulation accidents. Raman spectrum analysis technology can realize the non-destructive detection of gas samples with single wavelength laser,and has excellent applicability and efficiency for the detection of SF6 decomposition characteristic components. In this paper,a gas molecular model is established based on the B3LYP method of density functional theory(DFT). The molecular model is optimized by 6-311 G(2 df,p)basis set,and the Raman frequency shift characteristics are simulated. At the same time,four kinds of experimental platform of Raman spectrum detection are built based on Raman spectrum characteristics. The results show that there is a good correlation between the calculated and measured values of DFT and NIST standard values. The characteristic peaks of CF_(4),CO,H_(2)S and SO_(2) in the calculated values are 908.97,2 221.11,2 688.82,1 175.24 cm^(-1) respectively,which lays a foundation for the qualitative and quantitative analysis of SF6 decomposition characteristic components by Raman spectroscopy.