四氮烯异构体的密度泛函理论研究(英文)

A Density Functional Theory Investigation on the Isomers of Tetrazene

采用密度泛函理论对四氮烯起爆药的异构体进行研究。在B3LYP/6-311+G**水平下对四氮烯三种异构体分子的几何结构进行全优化计算。计算结果表明,(Ⅲ)的总能量比(Ⅰ)和(Ⅱ)都低,这说明(Ⅲ)是最稳定的分子结构,这与四氮烯的晶体结构和(Ⅲ)非常相近这一事实一致。对三种异构体分子的红外振动计算结果表明,它们的分子中都不存在虚频,由此说明这三种异构体都是可能存在的结构。由三种异构体分子的NBO电荷可以看出,(Ⅲ)分子中的原子排列比(Ⅰ)和(Ⅱ)便于分子中电荷的分散。前线轨道分析结果表明:N(8)是(Ⅲ)分子中最活跃的原子,在(Ⅲ)被活化的时候,N(8)—N(12)键先断裂。

Density functional method was applied to the study of the isomers of the primary explosive of tetrazene. The geometrical structures of the three isomers of tetrazene molecule which had been proposed formerly were fully optimized at the B3LYP/6-311 ＋G^＊＊ level of theory. The resuhs show that the total energy of （ Ⅲ） is less than that of （ Ⅰ ） and （Ⅱ） ,indicating that （ Ⅲ ） is the most stable structure,which is in agreement with the fact that tetrazene molecules in its crystal adopt structures similar to （ Ⅲ ）. The computational results of the IR vibration of the three isomers show that there is no imaginary frequency,which indicates that all of them are possibly existent structures. The NBO charges of the atoms of the three isomers show that the arrangement of atoms of （Ⅲ） facilitates the charge distribution better than （ Ⅰ ） and （ Ⅱ ）. It can be concluded from the frontier molecular orbital analysis that N （8） is the most active atom of tetrazene, and bond N（8）-N（12） will break first when it is activated.