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。%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.
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