Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
J Phys Chem A. 2009 Sep 17;113(37):9958-64. doi: 10.1021/jp905420v.
The structures and energetics of the reactants, intermediates, transition states, and products for the dissociation of methanimine neutral, monocation, dication, and trication were calculated at the CBS-APNO level of theory. The dissociations of the neutral, monocation, and dication were studied by ab initio direct classical trajectory calculations at the B3LYP/6-311G(d,p) level of theory. A microcanonical ensemble using quasiclassical normal mode sampling was constructed by distributing 200, 150, and 120 kcal/mol of excess energy above the local minima of the neutral, singly, and doubly charged species, respectively. Many of the trajectories dissociate directly to produce H+, H atom, or H2. However, for a fraction of the cases, substantial migration of the hydrogen occurs within the molecule before dissociation. The preferred dissociation product for the neutral and the monocation is hydrogen atom. Elimination of H(2) was seen in 20% of the trajectories for the neutral and in 5% of the trajectories for the monocation. Dissociations of the dication and trication produced H+ rather than H atom. HCNH+ was formed in 85-90% of the dissociating trajectories for the monocation and dication.
在 CBS-APNO 理论水平上计算了甲亚胺中性、一价正离子、二价正离子和三价正离子解离的反应物、中间体、过渡态和产物的结构和能量。通过在 B3LYP/6-311G(d,p)理论水平上的从头算直接经典轨迹计算研究了中性、一价正离子和二价正离子的解离。通过准经典正则模式采样构建微正则系综，在中性、单电荷和双电荷物种的局部最小值上分别分布 200、150 和 120 kcal/mol 的过剩能量。许多轨迹直接解离产生 H+、H 原子或 H2。然而，对于一部分情况，在解离之前，氢在分子内发生大量迁移。中性和一价正离子的首选解离产物是氢原子。在中性的 20%的轨迹中和一价正离子的 5%的轨迹中观察到 H2 的消除。二价正离子和三价正离子的解离产生 H+而不是 H 原子。在一价正离子和二价正离子的解离轨迹中，85-90%形成了 HCNH+。
