方解石晶体振动模式群论分析和红外光谱的DFT

分别运用因子群对称分析法和位置群对称分析法对方解石(CaCO3)晶体的振动模式进行了详细的理论分析,快速得到方解石晶体的具体振动模式,并明确指出了各振动模式的光谱特性,同时还比较了两种分析方法的适用性.对所建立的方解石晶体的超晶胞模型,采用基于密度泛函理论(DFT)的第一原理方法进行了红外光谱的计算,得到27个光学振动模式的具体振动频率,各频率的光谱特性与群论的理论分析一致.与晶格动力学方法相比,该方法的计算结果更好地符合实验结果.

Group Theory Based Analysis of Crystal Vibration Modes of Calcite and DFT Study on Its Infrared Spectra

The factor group symmetry analysis and position symmetry analysis were both used for the crystal vibration modes of calcite(CaCO3),and those modes were found definitely and rapidly with their spectral characteristics described separately.The applicabilities of the two analyses are compared with each other.In addition to the real spectra,the infrared spectra were calculated ab initio for the model we developed for calcite crystal supercell by introducing the first principle of DFT(density functional theory),and the frequencies of 27 optical vibration modes were obtained in every particular.The results showed that the spectral characteristics of each and all of the frequencies conform to those calculated theoretically by group theory.Compared with the lattice dynamics,the calculation results as above conform better to experimental results.