State Key Laboratory of Molecular Reaction Dynamics, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
Nat Commun. 2017 Jan 17;8:14094. doi: 10.1038/ncomms14094.
Encouraged by recent advances in revealing significant effects of van der Waals wells on reaction dynamics, many people assume that van der Waals wells are inevitable in chemical reactions. Here we find that the weak long-range forces cause van der Waals saddles in the prototypical C(D)+D complex-forming reaction that have very different dynamical effects from van der Waals wells at low collision energies. Accurate quantum dynamics calculations on our highly accurate ab initio potential energy surfaces with van der Waals saddles yield cross-sections in close agreement with crossed-beam experiments, whereas the same calculations on an earlier surface with van der Waals wells produce much smaller cross-sections at low energies. Further trajectory calculations reveal that the van der Waals saddle leads to a torsion then sideways insertion reaction mechanism, whereas the well suppresses reactivity. Quantum diffraction oscillations and sharp resonances are also predicted based on our ground- and excited-state potential energy surfaces.
受揭示范德华势阱对反应动力学的显著影响的最新进展的鼓舞，许多人认为范德华势阱在化学反应中是不可避免的。在这里，我们发现弱长程力在典型的 C(D)+D 复合物形成反应中导致了范德华鞍点，它们在低碰撞能下具有与范德华阱非常不同的动力学效应。在我们具有范德华鞍点的高精度从头算势能表面上进行精确的量子动力学计算，得到的截面与交叉束实验非常吻合，而在具有范德华阱的早期表面上进行相同的计算则在低能量下产生小得多的截面。进一步的轨迹计算表明，范德华鞍点导致扭转然后侧向插入反应机制，而阱则抑制反应性。基于我们的基态和激发态势能表面，还预测了量子衍射振荡和尖锐共振。
