BaBPO5晶体晶格振动光谱研究与第一性原理计算

通过偏振拉曼光谱和第一性原理计算对非线性光学晶体BaBPO₅的 晶格振动模式进行了研究. 实验得到了不同几何配置下、在100–1600 cm^-1范围内的晶体偏振拉曼光 谱与傅里叶变换红外吸收谱, 结合因子群分析方法研究了晶体的外振动与内振动模式特征. 分析表明拉曼振动主要来自于PO₄四面体和BO₄四面体的振动, 且PO₄基团振动具有较强的拉曼与红外活性. 此外,根据第一性原理对晶体拉曼振动进行了数值模拟, 进一步明确了拉曼峰与晶体中原子振动的对应关系, 计算表明拉曼光谱中位于672 cm^-1峰位来自晶体中B–O–P键的伸缩振动, 这是晶体中PO₄四面体和BO₄四面体共顶点连接的特征结构在光谱中的体现.

Vibrational spectra and first principles calculation of BaBPO5 crystal

In this paper, the lattice vibrational modes of the nonlinear optical crystal BaBPO₅ are studied using polarized Raman spectrum and the first-principles calculation. The polarized Raman spectra are obtained in different configurations and recorded in a range of 100-1600 cm^-1. Combining the experimental data of the FT-IR spectrum, the lattice vibrational modes of the internal and external vibrations are analyzed by the factor group analysis method. The results indicate that the primary Raman peaks of the BaBPO₅ crystal are ascribed to the internal vibrations of the PO₄ and BO₄ tetrahedrons, and the vibrations of the PO₄ tetrahedron show strong Raman- and IR-activity. On the other hand, the first-principles calculation indicates the correlation of the vibrational modes with the atomic activities. Especially, the Raman peak located at 672 cm^-1 is ascribed to the vibration of the B-O-P bond, which is the connector between the PO₄ and BO₄ tetrahedron. These results obtained in this work are important for understanding the micro-structures of the BaBPO₅ crystal, and the further study on the crystal growth mechanism.