氟/氯原子加甲烷分子及其同位素取代反应的态-态量子动力学研究

研究卤素原子与甲烷的反应对大气和燃烧化学有着重要的意义。而F+CH4和F+H2/HCl/H2O反应一样，得到的产物HF也有振动态布居反转，可以作为新的化学激光体系。理论方面，六原子反应体系的研究仍然是一个巨大的挑战。目前对F/Cl+CH4反应的动力学计算大多使用准经典轨线方法或局限在反应总截面，缺少能在量子态分辨层次上与实验直接比较的精确理论结果。本项目中，我们将运用神经网络方法构建F/Cl+CH4反应新的电子基态全维全域势能面，并发展X+YCZ3→XY+CZ3反应类型的7-8维态-态量子动力学方法与程序。我们将计算F/Cl+CH4/CHD3初始基态和部分振动激发态反应的微分截面，研究反应过程中是否存在共振态现象及其机理，研究CH4分子振动激发对产物末态分布的影响。这些工作与高分辨的交叉分子束实验结果结合，将推动多原子反应动力学的发展，还将为基于新反应途径的化学激光体系提供理论基础。

The reaction of halogen atom with methane is of great importance in both atmospheric and combustion chemistry. Similar to the F+H2/HCl/H2O reaction, the F+CH4 reaction has an inverted HF product vibrational state distribution, which can be used as the new HF chemical laser system. Theoretically, it is still a great challenge to study a six-atom reaction. Up to now, all the dynamical quantities were calculated by using QCT method or limited to total reactive cross sections, which were not able to compete in accuracy with state-of-the-art experiments. In this project, full-dimensional global PES for the ground electronic state of F/Cl+CH4 will be constructed using the neural networks method. The project is also aimed to develop and apply the state-to-state quantum dynamics theories and programs with seven/eight degrees of freedom to study the X+YCZ3→XY+CZ3 type reaction. We will calculate differential cross sections for F/Cl+CH4/CHD3 reaction from the ground and some vibrationally excited initial states. We will investigate reaction resonance phenomenon in the process and the effect of reagent vibrational excitation on a state-to-state level. With the cooperation of high-resolution, crossed-molecular beam experiment, the successful accomplishment of the project will not only push forward the development of polyatomic reaction dynamics field, but also provide theoretical foundations for developing new chemical laser systems.