Y_n(n=2～10)团簇的稳定结构及其光谱性能

Stable Structure and Spectral Properties of Y_n(n=2～10) Clusters

运用杂化密度泛函方法（DFT）B3LYP,在LANL2DZ赝势基组水平上对Yn（n=2~10）团簇的多种可能初始构型进行了结构优化和频率及光谱分析,根据能量最低原则确认了Yn（n=2~10）团簇没有虚频的基态结构,且计算得到的结构比以往理论计算得到的结构能量更低,Y2振动频率ωe=188.9 cm-1比以往计算值更接近实验值184.4 cm-1,在此基础上研究了团簇的稳定性和极化率,并分析了Yn（n=2~10）团簇的光谱性能。结果表明,Y7为所研究团簇结构转折点,团簇的电子稳定性随着原子数增加而逐渐减弱。振动光谱分析表明,Yn（n=2~10）团簇中具有较高对称性的C2v和Cs点群具有更多的振动模式,而稳定性较强的Y7和Y9在所研究频段内分别有较好的红外和拉曼活性,有明显的共振现象。

The possible geometric structures of Yn（n=2~10） clusters are executed with structural optimization and frequency analysis by using the density-functional theory（DFT） B3 LYP at the LANL2 DZ level. According to the lowest energy principle, the most stable structures without imaginary frequency for Yn（n=2~10） clusters are confirmed. The vibration frequency ωe=188.9 cm-1of Y2, which is closer to 184.4 cm-1of experimental data than the earlier calculated results. Based on this, the stability, polarizabilities of Yn（n=2~10） clusters are investigated, and the spectral properties of clusters are introduced. The results indicate that the structure of Y7 is a turning point among the structures of Yn（n=2~10） clusters. The electronic stability becomes weak with increasing the number of atoms. The vibrational spectra show that the Csand C2 vgroup have lots of vibration modes, the Y7 and Y9exhibit better infrared and Raman activity in the respective band and an obvious resonance phenomenon is found.