Si_4N_4团簇结构与性质的密度泛函理论研究(英文)

Density functional theory study on the structure and properties of Si_4N_4 clusters

用密度泛函理论(DFT)中的杂化密度泛函B3LYP方法,在6-31G(d)的水平上对Si4N4团簇的可能结构进行了几何结构优化和电子结构计算,得到了可能的17个异构体.Si4N4团簇的最稳定结构是有8个Si-N键的平面结构.用自然键轨道(NBO)方法分析了成键性质.计算结果表明,Si-N键中Si原子向N原子有较大的电荷转移,因此Si-N原子间有较强的电相互作用;最强的IR和Raman谱峰分别位于1387.64cm-1和1415.05cm-1处;并计算了Si4N4团簇的最稳定结构的极化率和超极化率.

The equilibrious geometries and electronic structures of possible isomers of Si4N4 clusters are studied by using density functional theory （DFT） with basis sets 6-31G^＊ 17 possible isomers are obtained. The most stable isomer of Si4N4 is a planar structure with 8 Si-N bonds. The bond properties of the most stable isomer was analyzed by using natural bond orbital method （NBO）, the results suggest that the charges on Si and N atoms in Si-N bonds are quite large, so the interaction of N-Si atoms in Si4N4 cluster is of strongly electric interaction, The primary IR and Raman vibration located at 1387.64cm^-1 and 1415.05cm^-1 respectively.The polarizabilities and hyperpolarizabilities of the most stable isomer are also analyzed.