MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged, H-6720, Hungary.
Phys Chem Chem Phys. 2022 Dec 7;24(47):29084-29091. doi: 10.1039/d2cp04416a.
A full-dimensional spin-orbit-corrected analytical coupled-cluster-quality potential energy surface (PES) is developed for the HI(XΣ) + CH → I(P) + CH reaction using the ROBOSURFER program package, and a quasi-classical trajectory (QCT) study on the new PES is reported. The stationary-point relative energies obtained on the PES reproduce well the benchmark values. Our simulations show that in the 0.5-40 kcal mol collision energy () range, the = 0 reaction probability, where denotes the impact parameter, increases first and then stays steady with increasing , reaching around 10% when = 5 kcal mol. No significant dependence is observed in the range of 5-40 kcal mol. The reaction probabilities decrease monotonically with increasing , and the maximum where the reactivity vanishes becomes smaller and smaller as increases. Scattering angle distributions show a forward scattering preference, indicating the dominance of the direct stripping mechanism, which is more obvious than in the case of HBr + CH → Br + CH. The reaction clearly favors H-side attack over side-on HI and the least-preferred I-side approach, and favors side-on CHCH attack marginally over CH-side and the least-preferred CH-side approach at high . At low , however, the dominant effect of H-side attack becomes weaker, while the side-on CHCH attack becomes comparable with CH-side and the former is a little less favored when = 0.5 kcal mol. It turns out that the initial translational energy is converted mostly into product recoil, whereas the reaction energy excites the CH vibration. The vibrational and rotational distributions of the CH product slightly blue-shift as increases, and none of the reactive trajectories violates the zero-point energy (ZPE) constraint. The energy transfer in the HI + CH → I + CH reaction is very similar to the case in the HBr + CH → Br + CH system that we investigated recently.
利用 ROBOSURFER 程序包，为 HI(XΣ) + CH → I(P) + CH 反应开发了一个全维自旋轨道修正分析耦合簇质量势能面（PES），并对新 PES 进行了准经典轨迹（QCT）研究。PES 上获得的驻点相对能很好地再现基准值。我们的模拟表明，在 0.5-40 kcal mol 碰撞能（）范围内， = 0 反应概率随着碰撞参数的增加先增加后保持稳定，当 = 5 kcal mol 时达到约 10%。在 5-40 kcal mol 范围内没有观察到明显的依赖性。反应概率随着的增加单调减小，反应性消失的最大值随着的增加而越来越小。散射角分布呈现前向散射偏好，表明直接剥离机制占主导地位，这比 HBr + CH → Br + CH 的情况更为明显。反应明显有利于 H 侧攻击而不是侧对 HI，最不优先的 I 侧接近，并且在高时稍微有利于侧对 CHCH 攻击而不是 CH 侧和最不优先的 CH 侧接近。然而，在低时，H 侧攻击的主导作用变弱，而侧对 CHCH 攻击变得与 CH 侧相当，当 = 0.5 kcal mol 时，前者稍微不那么有利。事实证明，初始平移能主要转化为产物反冲，而反应能激发 CH 振动。随着的增加，CH 产物的振动和转动分布略有蓝移，并且没有反应轨迹违反零点能（ZPE）约束。HI + CH → I + CH 反应中的能量转移与我们最近研究的 HBr + CH → Br + CH 系统非常相似。
