运用密度泛函理论(DFT)中的B3LYP方法,在6-311G(d)基组的水平上对Mg2Sin(n=1~9)团簇的多种可能几何构型进行了结构优化,获得了各个尺寸下团簇的最低能量结构,随后对最低能量构型的稳定性、红外光谱与拉曼光谱性质进行了理论研究。结果发现:当n≥3时,Mg2Sin团簇的基态构型均为立体结构;Mg原子的掺入提高了体系的化学活性;Mg2Si4与Mg2Si6是幻数结构;在相同的观察频段内,Mg2Si4团簇的红外光谱只有一个强振动峰,拉曼光谱强振动峰的个数较多且位于高频段内,其拉曼活性较强,与之相反,Mg2Si6团簇的红外光谱强振动峰个数较多,而拉曼光谱强振动峰则只有一个,表明其红外活性较强。 Using the B3LYP method in density functional theory (DFT), a variety of possible geometrical configurations of Mg2Sin (n = 1 ~ 9) clusters have been structurally optimized at the 6-311G (d) basis. The lowest energy structure of the clusters under each size, followed by a theoretical study of the stability of the lowest energy configuration, the infrared and Raman spectral properties. The results show that the ground state configurations of Mg2Sin clusters are all three-dimensional structures when n≥3; the incorporation of Mg atoms improves the chemical activity of the system; Mg2Si4 and Mg2Si6 are magic number structures; in the same observation frequency band, Mg2Si4 clusters The infrared spectrum of cluster has only one strong vibration peak, and the number of strong vibration peaks of Raman spectrum is large and located in high frequency range, and its Raman activity is strong. On the contrary, the strong peak of infrared spectrum of Mg2Si6 cluster However, there is only one strong vibration peak of Raman spectrum, which indicates that it has strong infrared activity.