Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, USA.
J Chem Phys. 2013 May 7;138(17):174502. doi: 10.1063/1.4798457.
A new polarizable water model is developed for molecular dynamics (MD) simulations of the proton transport process. The interatomic potential model has three important submodels corresponding to electrostatic interactions, making and breaking of covalent bonds, and treatment of electron exchange and correlation through a van der Waals potential. A polarizable diffuse charge density function was used to describe Coulombic interactions between atoms. Most of the model parameters were obtained from ab initio data for a lone water molecule. Molecules respond realistically to their electrochemical environment by the use of coupled fluctuating charge and fluctuating dipole dynamics, which controlled the charge density. The main purpose of the work is to develop a general model and framework for future studies, though some validation work was performed here. We applied the model to a MD simulation study of bulk properties of liquid water at room temperature and model gave good agreement with thermodynamic and transport properties at the same conditions. The model was then applied to a preliminary study of proton transfer, in which multiple proton transfer events were observed, though the rate of proton transfer was under-predicted by a factor of 5.
一种新的可极化水分子模型被开发出来，用于质子输运过程的分子动力学（MD）模拟。该原子间相互作用势能模型有三个重要的子模型，分别对应于静电相互作用、共价键的形成和断裂，以及通过范德华势能处理电子交换和相关。一个可极化的弥散电荷密度函数被用来描述原子之间的库仑相互作用。该模型的大多数参数都是从孤立水分子的从头算数据中获得的。通过使用耦合的涨落电荷和涨落偶极子动力学，分子可以真实地响应它们的电化学环境，从而控制电荷密度。这项工作的主要目的是开发一个通用的模型和框架，以供未来的研究使用，尽管这里也进行了一些验证工作。我们将该模型应用于室温下液态水的体性质的 MD 模拟研究，该模型在相同条件下与热力学和输运性质吻合良好。然后，我们将该模型应用于质子转移的初步研究，在该研究中观察到了多个质子转移事件，尽管质子转移的速率被低估了 5 倍。
