密度泛函理论研究SiCmN团簇

用密度泛函理论(DFT)的B3LYP/6-311G*方法，对SiCmN(m=1-7)团簇的几何构型、振动频率和基态能量等性质进行了研究，讨论了化学键的特征和热力学稳定性。振动频率和振动强度被用来判断体系的基态结构。结果表明，m=1~5的团簇为线状结构，m=6、7的团簇为环状结构。m增大过程中，线状团簇自旋多重度均为2，而环状团簇出现2、4和6自旋多重度。能量的二次差分值表明m为奇数的团簇比m为偶数的更为稳定。

A density functional study of SiCmN Clusters

In this paper, density functional theory(DFT) B3LYP method with 6-311G* basis set has been used to investigated geometries, vibrational frequencie and ground state energies of SiCmN(m=1-7) clusters. The character of chemical bond and thermodynamic stability of isomers has been discussed. Harmonic frequencies and infrared spectra intensity for these clusters are given in order to aid in the characterization of the ground states. The results show that SiCmN(m=1-5) clusters form linear structures and SiCmN(m=6-7) clusters form ring structures. The linear structure clusters are doublet states and the ring structure ones are doublet, quartet and sextet states with increasing values of m. The stability of SiCmN(m=1-7) clusters with odd m are greater than that with even m.