论文标题
在乙醛中漫游
Roaming in acetaldehyde
论文作者
论文摘要
我们研究了在乙醛（Ch $ _3 $ CHO）的光解离时漫游，提供了与甲醛相比观察到的该分子的对比漫游动力学的见解。我们进行全维乙醛的轨迹研究，并补充了对两个自由度限制模型的分析，并获得了两种不同的漫游途径的证据。轨迹在较短（9-11.5 au）和较大（14.5-22.9 au）最大CH $ _3 $ -HCO分离的轨迹上漫游，其特征是HCO旋转量不同。在中间的间隙区域未发现漫游轨迹。接近14.5-22.9 au的漫游动力学是由限制模型的精心生成的，涉及通过类似于甲醛漫游的离心屏障。但是，较短的范围9-11.5 Au漫游似乎是乙醛独特的，并且很可能会因简化模型中缺乏排斥相互作用而促进。相空间分析表明，在降低的维度系统中，这种附加的漫游途径无法访问。研究结果表明，与甲醛相比，乙醛的漫游倾向增加可能是由于存在多种不同的漫游机制而不仅仅是较高的漫游片段。
We investigate roaming in the photodissociation of acetaldehyde (CH$_3$CHO), providing insight into the contrasting roaming dynamics observed for this molecule compared to formaldehyde. We carry out trajectory studies for full-dimensional acetaldehyde, supplemented with an analysis of a two degree-of-freedom restricted model and obtain evidence for two distinct roaming pathways. Trajectories exhibit roaming at both shorter (9-11.5 au) and larger (14.5-22.9 au) maximum CH$_3$-HCO separations, characterized by differing amounts of HCO rotation. No roaming trajectories were found in the intervening gap region. The roaming dynamics near 14.5-22.9 au are well-reproduced by the restricted model and involve passage through a centrifugal barrier, analogous to formaldehyde roaming. However, the shorter-range 9-11.5 au roaming appears unique to acetaldehyde, and is likely facilitated by repulsive interactions absent in the simplified models. Phase space analysis reveals that this additional roaming pathway is inaccessible in the reduced dimensionality system. The findings suggest acetaldehyde's increased propensity for roaming compared to formaldehyde may arise from the presence of multiple distinct roaming mechanisms rather than solely the higher roaming fragment mass.
