Nuclear Quantum Effects Largely Influence Molecular Dissociation and Proton Transfer in Liquid Water under an Electric Field
Nuclear Quantum Effects Largely Influence Molecular Dissociation and Proton Transfer in Liquid Water under an Electric Field
复制标题
DOI：
10.1021/acs.jpclett.0c02581
复制
发表时间：
2020-11-05
影响因子：
5.7
通讯作者：
Cassone, Giuseppe
中科院分区：
文献类型：
--
作者：
Cassone, Giuseppe
液态水中的质子转移控制着酸碱化学、关键的酶反应和燃料电池的功能。外部施加在水中的静电场能够解离分子并通过氢键网络转移质子。然而，核量子效应（NQEs）对这些基本场致现象的影响尚未报道。通过比较最先进的从头算分子动力学（AIMD）和电场下水的路径积分AIMD模拟，我表明质子的量子离域将分子电离阈值降低到大约三分之一。此外，作为质子半导体的水的行为也被NQEs的加入大大改变了。事实上，当考虑到原子核的量子性质时，质子的导电性差不多要大50%。本工作证明了NQEs对室温液态水的质子水解现象和质子转移有较大的影响。
Proton transfer in liquid water controls acidbase chemistry, crucial enzyme reactions, and the functioning of fuel cells. Externally applied static electric fields in water are capable of dissociating molecules and transferring protons across the H-bond network. However, the impact of nuclear quantum effects (NQEs) on these fundamental field-induced phenomena has not yet been reported. By comparing state-of-the-art ab initio molecular dynamics (AIMD) and path integral AIMD simulations of water under electric fields, I show that quantum delocalization of the proton lowers the molecular ionization threshold to approximately one-third. Moreover, also the water behavior as a protonic semiconductor is considerably modified by the inclusion of NQEs. In fact, when the quantum nature of the nuclei is taken into account, the proton conductivity is similar to 50% larger. This work proves that NQEs sizably affect the protolysis phenomenon and proton transfer in room-temperature liquid water.