氢原子与烃类分子高速碰撞中的超级能量转移

能量转移是分子反应动力学领域的重要研究方向。最近，申请人作为理论第一完成人与美国科学家合作研究发现，在H原子和乙炔分子的高速碰撞过程中存在"超级能量转移"现象，即较大部分的乙炔分子在碰撞中产生了显著的振动激发。以往的理论模型难以解释该现象，这是能量转移研究中的新课题。本项目针对H原子与烃类分子(C2H2,C2H4,C2H6及同位素取代物)的高速碰撞过程开展研究。通过交换不变多项式拟合方法构建以上体系全维全域势能面，并采用准经典轨线方法开展动力学研究。在不同碰撞能条件下，深入探讨反应络合物的产生概率、交换反应通道与非弹性碰撞通道的分支比、交换反应相关的反应机理等与烃分子饱和度之间的关系，并确定这三种关系对能量转移分布函数的影响，最终建立烃类分子饱和度与超级能量转移难易程度之间的关系。为深入认识超级能量转移这一新的现象提供理论依据，并为实验上寻找可能存在此现象的碰撞体系提供理论预测。

Energy transfer is one of the most important research topics in the field of molecular reaction dynamics. Recently, in the cooperative research with the scientists in the US, we found that in the high speed collision between the H atoms and the acetylene molecules, a phenomenon called "super energy transfer" takes place, i.e., a considerable amount of the acetylene molecules are significantly vibrationally excited. This phenomenon cannot be explained by previous theoretical models, and thus it is a new topic in the study of energy transfer. In this project, we will perform studies focusing on the high speed collisions between the H atoms and the C2H2,C2H4, or C2H6 molecules and the corresponding isotopes. The global full-dimensional potential energy surfaces are constructed by using the permutationally invariant polynomial fitting method and the dynamics studies are carried out by using the quasi-classical trajectory method. At various collision energies, we will deeply investigate the correlations between the degree of saturation of the hydrocarbon molecules and the probability of the reaction complex formation, the branching ratio of the exchange reaction channel to the inelastic collision channel, and the reaction mechanisms of the exchange reaction. By determining the contributions of the above three correlations to the energy transfer distribution function, we can finally establish the relationship between the degree of saturation of the hydrocarbon molecules and the feasibility of super energy transfer. We aim to provide the theoretical foundation for a deeper understanding of this new phenomenon of super energy transfer, and to further provide the theoretical prediction for the discovery of super energy transfer in collision systems by experiment.