论文标题
S $ _n $ 2反应的溶剂反应坐标
Solvent reaction coordinate for an S$_N$2 reaction
论文作者
论文摘要
我们研究了原型SN2反应Cl $^ - $ + CH $ _3 $ Cl $ \ to $ ch $ _3 $ _3 $ cl + Cl + Cl $ cl + Cl $^ - $使用量子力学 /分子力学（QM / mm）计算机模拟，具有过渡路径采样和惯性可能性最大化。我们已经确定了一种新的溶剂坐标，以补充Chandrasekhar，Smith和Jorgensen的经典分析中使用的原子 - 交换坐标[Ref1]。新的溶剂坐标量化了瞬时溶剂诱导的极化相对于沿着反应途径的每个点的平均平均电荷密度。根据似然得分和委员会分布，相对于先前提出的溶剂坐标的描述，新的溶剂坐标会改进。但是，它不会增加传输系数或过渡状态理论速率计算的准确性。
We study the prototypical SN2 reaction Cl$^-$ + CH$_3$Cl $\to$ CH$_3$Cl + Cl$^-$ in water using quantum mechanics / molecular mechanics (QM/MM) computer simulations with transition path sampling and inertial likelihood maximization. We have identified a new solvent coordinate to complement the original atom-exchange coordinate used in the classic analysis by Chandrasekhar, Smith, and Jorgensen [Ref1]. The new solvent coordinate quantifies instantaneous solvent induced polarization relative to the equilibrium average charge density at each point along the reaction pathway. On the basis of likelihood scores and committor distributions, the new solvent coordinate improves upon the description of solvent dynamical effects relative to previously proposed solvent coordinates. However, it does not increase the transmission coefficient or the accuracy of a transition state theory rate calculation.
