二氧化三氮(N_3O_2)中性分子和离子的一些重要反应过程的理论研究

Theoretical Studies on Some Important Reactions of N_3O_2 Ion and Neutral Molecule

二重态的N3O2中性分子作为中间体,在N3O2阴离子的光解离反应和NO+N2O N2+NO2反应中均起重要作用.在CCSD(T)/6-311G(d,p)//B3LYP/6-311G(d,p)+ZPE的水平上,对这两个反应进行了理论计算.结果表明,在N3O2阴离子的光解离反应中,该阴离子先在光照下解离为与其具有相同的W构型的中性分子和一个电子,这个中性分子是一个过渡态,它将打破C2v构型变成具有Cs对称性的W型中间异构体,然后再经过一个过渡态,裂解成N2O+NO两个小分子.这个裂解过程的能垒非常低(5.96 kJ/mol),因此在实验中很难检测到W型的中间异构体.在另一个重要的[N3O2]体系的反应(NO+N2O N2+NO2)中,找到了两条反应通道,其中不经过中间异构体的一步转化通道更为可行.

In this article, some important characters about neutral N3O2 molecule such as its dissociations and the key reaction NO ＋ N2O →←N2 ＋ NO2 were investigated at CCSD（ T）/6-311G（ d,p）//B3LYP/6-311 G （d,p） ＋ZPE levels. The optimized geometries of neutral N3O2 are W shape and five-membered ring isomer. However, the energies of the two isomers are so high that they would rather dissociate to some other small molecules. In the photolysis of the N3O2 negative ion, such a process is confirmed as N3O2^- ＋ hv→TSI（ W shape neutral N3O2 molecule with C2v symmetry） ＋ e^→m1 （W shape neutral N3O2 molecule with C, symmetry） ＋ e →TS2 ＋ e^- →N2O ＋ NO ＋ e. Because the barrier near TS2 is very low （ only 5.96 kJ/mol）, the life of ml is so short that it can hardly be detected in the experiments. In the key reaction NO ＋ N2O →←N2 ＋ NO2, both barriers of multicomponent reaction and elementary reaction are high. But the elementary reaction is easier than the muhicomponent reaction.