Department of Physics, Karaj Branch, Islamic Azad University, Karaj, Iran.
Institut für Ionenphysik und Angewandte Physik, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
J Chem Phys. 2018 Feb 21;148(7):074301. doi: 10.1063/1.5013606.
Dissociative electron attachment to three isomers of bromo-chlorotoluene was investigated in the electron energy range from 0 to 2 eV for gas temperatures in the range of 392-520 K using a crossed electron-molecular beam apparatus with a temperature regulated effusive molecular beam source. For all three molecules, both Cl and Br are formed. The ion yields of both halogenides show a pronounced temperature effect. In the case of Cl and Br, the influence of the gas temperature can be observed at the threshold peak close to 0 eV. The population of molecules that have some of their out-of-plane modes excited varies strongly in the temperature range investigated, indicating that such vibrations might play a role in the energy transfer towards bond breaking. Potential energy curves for the abstraction of Cl and Br were calculated and extrapolated into the metastable domain. The barriers in the diabatic curves approximated in this way agree well with the ones derived from the temperature dependence observed in the experiments.
用交叉电子-分子束装置和温度可调的扩散分子束源，在电子能量范围为 0 到 2eV，气体温度范围为 392-520K 的条件下，研究了溴氯甲苯的三种异构体的电子离解。对于所有三种分子，都形成了 Cl 和 Br。两种卤化物的离子产率都表现出明显的温度效应。对于 Cl 和 Br，在接近 0eV 的阈值峰处可以观察到气体温度的影响。在研究的温度范围内，平面外模式被激发的分子数量发生了强烈的变化，这表明这种振动可能在向键断裂的能量转移中发挥作用。Cl 和 Br 的提取势能曲线被计算并外推到亚稳域。以这种方式近似的非绝热曲线的势垒与从实验中观察到的温度依赖性得出的势垒很好地吻合。
