论文标题
水离子溶液中的量子动能和同位素分馏
Quantum kinetic energy and isotope fractionation in aqueous ionic solutions
论文作者
论文摘要
在室温下，对水分子的动能的量子贡献超过了经典的数量级。水分子的量子动能（QKE）是由其局部化学环境调节的，并导致热平衡中不同相之间同位素的分配不平衡，如果核表现出经典，这将不会发生。在这项工作中，我们使用Ab Initio路径积分模拟来表明水分子的QKE和氧和氢同位素的平衡同位素分馏率是水平离子溶液中氢键结构的敏感探针。特别是，我们证明了如何将水分子QKE分解为自由度的转化，旋转和振动程度，并使用它们来确定溶剂化对不同分子运动的影响。通过分析QKE和同位素分级比率，我们展示了Na $^+$，Cl $^ - $和HPO $ _4^{2-} $ ions的添加如何播放液体水中的量子效应之间的竞争并影响其本地求解结构。
At room temperature, the quantum contribution to the kinetic energy of a water molecule exceeds the classical contribution by an order of magnitude. The quantum kinetic energy (QKE) of a water molecule is modulated by its local chemical environment and leads to uneven partitioning of isotopes between different phases in thermal equilibrium, which would not occur if the nuclei behaved classically. In this work, we use ab initio path integral simulations to show that QKEs of the water molecules and the equilibrium isotope fractionation ratios of the oxygen and hydrogen isotopes are sensitive probes of the hydrogen bonding structures in aqueous ionic solutions. In particular, we demonstrate how the QKE of water molecules in path integral simulations can be decomposed into translational, rotational and vibrational degrees of freedom, and use them to determine the impact of solvation on different molecular motions. By analyzing the QKEs and isotope fractionation ratios, we show how the addition of the Na$^+$, Cl$^-$ and HPO$_4^{2-}$ ions perturbs the competition between quantum effects in liquid water and impacts their local solvation structures.
