甲醇锂和乙醇锂拉曼光谱的密度泛函理论研究

Study of Density Functional Theory (DFT) for Raman Spectra of CH_3OLi and CH_3CH_2OLi

前人研究证明在烷氧基锂(ROLi)中锂原子直接和氧原子相连而形成O—Li健,作者依此构造出甲醇锂和乙醇锂的分子构型。目前在实验和理论计算上都尚无对甲醇锂和乙醇锂分子的拉曼光谱的报道。文章用密度泛函理论中的B3LYP混合泛函联合6-31G(d,p)基函数组进行了这两个分子的结构优化得到其平衡构型。基于此平衡构型计算出甲醇锂和乙醇锂的振动频率和拉曼光谱,对计算所得的振动频率进行了简正坐标分析,根据各频率的势能分布进行了全面的归属指认,旨在为用拉曼光谱技术研究和分析锂离子电池固体电解质膜(SEI膜)组分提供更多的理论依据。

Molecular configurations of CH3OLi and CH3CH2OLi were structured based on the previous study that lithium atom and oxygen atom are directly joined by O-Li bond in alkoxy lithium （ROLi）. Neither experimental nor theoretical Raman spectra of CH3OLi and CH3CH2OLi have been reported up to now. In the present paper,DFT method at the B3LYP/ 6-31G（d,p） level was used to optimize molecular configurations of CH3OLi and CH3CH2OLi,obtaining each corresponding equilibrium configuration. Vibration frequencies and Raman spectra of these two molecules were calculated based on equilibrium configuration. The vibration frequencies of obtained calculated results were analyzed by normal coordinate analysis. Besides,the Raman vibration modes of CH3OLi and CH3CH2OLi were assigned according to potential energy distribution of each vibration frequency,which will provide theoretical basis for experimental workers to analyze the components of solid electrolyte interface film （SEI film） of lithium ion battery.