原子团簇N_8的分子模型设计与量子化学计算

Molecular Model Design and Quantum Chemistry Calculation of Cluster N_8

根据N5+ 和N3- 两种离子的存在 ,预测可能存在原子团簇N8.使用分子模拟软件设计出 2 0种N8的同分异构体 ,然后采用量子化学从头算方法在HF/STO_3G理论水平下对各个分子进行了全构型优化、热力学计算和谐振频率分析 ,最后讨论了N8的实验合成路线 .计算结果表明 ,有 12种同分异构体可稳定存在 ,其中平面双五元环结构 (D2h)最为稳定 .能量分析表明 ,可稳定存在结构的N8含有比 4个N2 高得多的能量 ,如果能够合成出N8,将会成为潜在的绿色高能量密度材料 .

The existence of cluster N_8 was predicted according to the existence of N_5 + and N_3 -. Twenty N_8 isomers were then designed by using the molecular simulation software. The full geometry optimization,thermodynamics calculation and harmonic vibration frequency analysis of these twenty N_8 molecules were performed at the HF/STO-3G level with the ab initio method of quantum chemistry. The synthesis routes of N_8 in experiments were finally discussed. The calculated results show that twelve of the twenty N_8 isomers can stably exit,and that the planar double five-member ring form of N_8 with D_ 2h symmetry is the most stable. Energy analysis result indicates that a N_8 molecule with a stable structure contains much higher energy than four N_2 molecules,which means N_8 is a potential green material with high energy density.