基于密度泛函理论的SinCN团簇结构及稳定性的研究

A density functional study of structures and stability of Si_nCN clusters

利用密度泛函理论（DFT）中的B3LYP／6—311G＊方法，对SinCN（n=2～6）团簇的几何结构、振动频率和基态能量等性质进行了研究，分别讨论了其基态和亚稳态结构的能量及自旋多重态．振动频率和振动强度被用来判断体系的稳定性．结果表明，随着Si原子数的增加，零点振动能、热容量和熵近似线性增长，其平均增幅分别为0．80kcal／mol、5．20cal／mol·K和12．72cal／mol·K．n为偶数的SinCN团簇比n为奇数的更为稳定．

In this paper, density functional theory（DFT） B3LYP method with 6-311G＊ basis set has been used to investigate geometric configurations, vibrational frequencies and ground state energies of SinCN （n=2-6） clusters. The energies and spin multiplicities of ground states and substable states have been discussed, respectively. Harmonic frequencies and infrared spectra intensity for these clusters are given in order to aid in the characterization of the stable structures. The results show that the zero point energy （ZPE）, thermocapacity and entropies are nearly in proportion to increased n, whose average enhancement are 0.80 kcal/mol, 5.20 cal/mol ·K and 12.72 cal/mol· K, respectively. The stability of SinCN （n=2-6） clusters with even n are greater than that with odd n.