Density functional theory study on the structure and properties of Si3N4 clusters

摘要

The hybrid density functional theory B3LYP with basis sets 6-31G· has been used to study on the equilibrium geometries and electronic structures of possible isomers of Si3N4 clusters. 24 possible isomers are obtained. The most stable isomer of Si3N4 is a 3D structure with 7 Si-N bonds and 2 N-N bonds that could be formed by 3 quadrangles. 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 Si3N4 cluster is of strongly electric interaction. The primary IR and Raman vibrational frequency located at 1033.40 cm-1, 473.63 cm-1 respectively. The polarizabilities and hyperpolarizabilities of the most stable isomer are also analyzed.