SinC2N团簇结构及稳定性的密度泛函理论研究

A density functional study of structures and stability of Si_n C_2N clusters

利用密度泛函理论（DFT）中的B3LYP／6—311G·方法，对SkC2N（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，其平均增幅分剐为1．03kcal／mol、4．84cal／mol·K和11．96cal／mol·K．13．为奇数的SinC2N团簇比n为偶数的更为稳定．

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 SinC2N （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 enhance- ment are 1.03 kcal/mol, 4.84 cal/mol · K and 11.96 cal/mol · K, respectively. The stability of SinC2N （n=2~6） clusters with odd m are ~reater than that with even n.