Paricaud Patrice, Predota Milan, Chialvo Ariel A, Cummings Peter T
Department of Chemical Engineering, Vanderbilt University, Nashville, Tennesee 37235-1604, USA.
J Chem Phys. 2005 Jun 22;122(24):244511. doi: 10.1063/1.1940033.
Water exhibits many unusual properties that are essential for the existence of life. Water completely changes its character from ambient to supercritical conditions in a way that makes it possible to sustain life at extreme conditions, leading to conjectures that life may have originated in deep-sea vents. Molecular simulation can be very useful in exploring biological and chemical systems, particularly at extreme conditions for which experiments are either difficult or impossible; however this scenario entails an accurate molecular model for water applicable over a wide range of state conditions. Here, we present a Gaussian charge polarizable model (GCPM) based on the model developed earlier by Chialvo and Cummings [Fluid Phase Equilib. 150, 73 (1998)] which is, to our knowledge, the first that satisfies the water monomer and dimer properties, and simultaneously yields very accurate predictions of dielectric, structural, vapor-liquid equilibria, and transport properties, over the entire fluid range. This model would be appropriate for simulating biological and chemical systems at both ambient and extreme conditions. The particularity of the GCPM model is the use of Gaussian distributions instead of points to represent the partial charges on the water molecules. These charge distributions combined with a dipole polarizability and a Buckingham exp-6 potential are found to play a crucial role for the successful and simultaneous predictions of a variety of water properties. This work not only aims at presenting an accurate model for water, but also at proposing strategies to develop classical accurate models for the predictions of structural, dynamic, and thermodynamic properties.
水具有许多对生命存在至关重要的独特性质。水在从环境条件到超临界条件的转变过程中，其性质会发生彻底改变，这种改变使得在极端条件下维持生命成为可能，这引发了关于生命可能起源于深海热液喷口的推测。分子模拟在探索生物和化学系统方面非常有用，特别是在实验困难或无法进行的极端条件下；然而，这种情况需要一个适用于广泛状态条件的精确水的分子模型。在此，我们基于Chialvo和Cummings [《流体相平衡》，150, 73 (1998)] 早期开发的模型提出了一种高斯电荷极化模型（GCPM），据我们所知，这是第一个既能满足水单体和二聚体性质，又能在整个流体范围内对介电、结构、气液平衡和传输性质做出非常准确预测的模型。该模型适用于模拟环境条件和极端条件下的生物和化学系统。GCPM模型的独特之处在于使用高斯分布而非点来表示水分子上的部分电荷。这些电荷分布与偶极极化率和Buckingham exp - 6势相结合，被发现对于成功同时预测多种水的性质起着关键作用。这项工作不仅旨在提出一个精确的水模型，还旨在提出开发用于预测结构、动力学和热力学性质的经典精确模型的策略。
