Pizzochero Michele, Ambrosio Francesco, Pasquarello Alfredo
Chaire de Physique Numérique de la Matière Condensée (C3MP) , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland . Email:
Chaire de Simulation à l'Echelle Atomique (CSEA) , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland.
Chem Sci. 2019 Jun 19;10(31):7442-7448. doi: 10.1039/c8sc05101a. eCollection 2019 Aug 21.
A transient state of the excess electron in liquid water preceding the development of the solvation shell, the so-called wet electron, has been invoked to explain spectroscopic observations, but its binding energy and atomic structure have remained highly elusive. Here, we carry out hybrid functional molecular dynamics to unveil the ultrafast solvation mechanism leading to the hydrated electron. In the pre-hydrated regime, the electron is found to repeatedly switch between a quasi-free electron state in the conduction band and a localized state with a binding energy of 0.26 eV, which we assign to the wet electron. This transient state self-traps in a region of the liquid which extends up to ∼4.5 Å and involves a severe disruption of the hydrogen-bond network. Our picture provides an unprecedented view on the nature of the wet electron, which is instrumental to understanding the properties of this fundamental species in liquid water.
在溶剂化壳层形成之前，液态水中存在过量电子的瞬态状态，即所谓的湿电子，人们曾用它来解释光谱观测结果，但其结合能和原子结构一直非常难以捉摸。在这里，我们进行混合泛函分子动力学研究，以揭示导致水合电子的超快溶剂化机制。在预水合阶段，发现电子在导带中的准自由电子态和结合能为0.26 eV的局域态之间反复切换，我们将后者归因于湿电子。这种瞬态状态自陷在液体的一个区域中，该区域延伸至约4.5 Å，并且涉及氢键网络的严重破坏。我们的描述提供了关于湿电子性质的前所未有的观点，这有助于理解液态水中这种基本物种的性质。
