凝聚相化学反应中动力学效应的重要性研究  

The importance of dynamic effects in chemical reactions in condensed phase

作　　者：雷曜坤 张骏 张珍 高毅勤[1,2,3,5] Yao-Kun Lei;Jun Zhang;Zhen Zhang;Yi-Qin Gao(Institute of Theoretic and Computational Chemistry,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China;Beijing National Laboratory for Molecular Sciences,Beijing 100871,China;Shenzhen Bay Laboratory,Shenzhen 518000,China;Department of Physics,Tangshan Normal University,Tangshan 063000,China;Biomedical Pioneering Innovation Center,Peking University,Beijing 100871,China)

机构地区：[1]北京大学化学与分子工程学院,北京100871 [2]北京分子科学国家研究中心,北京100871 [3]深圳湾实验室,深圳518000 [4]唐山师范大学物理学院,唐山063000 [5]北京大学生物医学前沿创新中心,北京100871

出　　处：《中国科学：化学》2020年第10期1407-1421,共15页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(编号:21927901,21821004,21873007);国家重点研发计划(编号:2017YFA0204702)资助项目。

摘　　要：能量活化、空间扩散是化学反应中极为重要的两个子过程.传统的速率理论建立在两个假设之上:(1)能量传递的速率远快于化学转化,从而具体的能量通路并不重要;(2)溶剂能够对溶质的变化进行快速响应,从而达到平衡溶剂化,体系一旦越过能垒则不再折回.然而当能量传递的时间尺度并不足够快,以至于能量不能迅速按比例分配到各自由度时,特定的能量转移通路就显得十分重要.而我们之前的工作发现化学反应中溶质溶剂间的能量传输主要通过特定的极性官能团来进行,并具备模式特异性,更换溶剂可以改变能量传输通道.此外,由于体系穿越势垒的时间是极短的,溶剂可能无法及时调整,导致体系处于暂态的非平衡溶剂化构象,而不同的非平衡溶剂化构象中溶质溶剂具有不同强度的相互作用,从而可使得反应路径更为多样化.所以理解化学反应中的动力学因素对我们理解、调控化学反应极其重要.Energy transfer and spatial diffusion are two significant sub-processes in chemical reaction. Traditional rate theory is based on two assumptions:(1) energy transfer is faster than chemical reaction so that specific energy transfer channel is not important.(2) The solvents can respond to the change of solute quickly resulting in equilibrium solvation.Then once system cross the barrier, it will enter the product basin. But when energy transfer is fast enough to distribute the energy into all degrees of freedom according to certain ratio, the specific energy transfer pathways should be considered. Our previous studies have found that the polar functional groups play the major role in the intermolecular energy transfer process. And the energy accumulation and dissipation are completed by the motion with specific frequency. Furthermore, the major energy transfer channel is different in different solutions. Moreover, the length of transition path is very short, leading to the existence of different transient solvation configurations with distinctly different strengths of interaction between solutes and solvents. Consequently, the motion of solvents modulates the reaction dynamics and results in heterogeneous reaction paths. Therefore, the dynamic effects are vital for understanding and controlling the chemical reaction.

关 键 词：动力学效应 能量传递 非平衡溶剂化 外电场 

分 类 号：O643.1[理学—物理化学]