A recent guided ion beam study of the HCl + HCl⁺ reaction has revealed two different products [Phys. Chem. Chem. Phys. 2015, 17 (25), 16454–16461]. The first is the proton transfer product, H₂Cl⁺ + Cl, where the cross section of the reactions associated with this product, as predicted, monotonically decreases as the collision energy between the product increases. The second is the product HCl⁺ + HCl, where the cross section of the reaction shows a local maximum at the collision energy of 0.5 eV. The nature of this unusual behavior of the cross section is not clear. In this manuscript, state of the art ab initio molecular dynamics (AIMD) simulation is performed to study this bimolecular collision of HCl⁺ + HCl. The potential energy of profile of this system is first characterized with high-level ab initio methods, and then a computationally efficient method is selected for AIMD simulation. The cross sections from AIMD agree well with those from the experiments for both products. The AIMD trajectories reveal the complexity of this seemingly-simple reaction – a total of five different pathways that result in the aforementioned two products. The simulation also sheds light on the mystery of the local maximum of the cross section regarding the HCl⁺ + HCl product.

最近对HCl + HCl ⁺反应进行的引导离子束研究发现了两种不同的产物[ Phys。化学 化学 物理 2015年，17（25），16454-16461]。第一个是质子转移产物H ₂ Cl ⁺  + Cl，其中与该产物相关的反应截面如所预测的随着产物之间的碰撞能量增加而单调减小。第二个是产物HCl ⁺  + HCl，其中反应的横截面在碰撞能量为0.5 eV时显示出局部最大值。横截面这种异常行为的性质尚不清楚。在该手稿，状态在本领域的从头进行分子动力学（AIMD）模拟以研究HCl ⁺  + HCl的这种双分子碰撞。该系统轮廓的势能首先用高级从头算方法来表征，然后选择一种计算有效的方法进行AIMD仿真。AIMD的横截面与两种产品的实验都非常吻合。AIMD的轨迹揭示了这种看似简单的反应的复杂性-共有五种不同的途径产生了上述两种产物。模拟还阐明了关于HCl ⁺  + HCl产物的横截面局部最大值的奥秘。