Water Modeled As an Intermediate Element between Carbon and Silicon
Water Modeled As an Intermediate Element between Carbon and Silicon
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DOI：
10.1021/jp805227c
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发表时间：
2009-04-02
影响因子：
3.3
通讯作者：
Moore, Emily B.
中科院分区：
文献类型：
--
作者：
Molinero, Valeria;Moore, Emily B.
水和硅是化学性质不同的物质，但具有共同的物理性质。它们的液体表现出最大密度的温度，压缩时扩散率增加，并且它们形成四面体晶体和四面体非晶相。水、硅和碳的共同特征是形成四面体配位单元。我们利用这些相似性开发了水的粗粒度模型（mW），它本质上是一个介于碳和硅之间的四面体原子。 mW 通过引入促进四面体构型的非键角相关项来模拟水的氢键结构。该模型背离了水建模中的流行范例：使用远程力（静电）来产生短程（氢键）结构。毫瓦仅具有短程相互作用，但它可以再现液态水的能量、密度和结构及其异常和相变，其精度与最流行的水原子模型相当或更好，计算成本不到 1%。我们的结论是，决定水的结构和热力学行为的不是相互作用的本质，而是分子的连通性。 mW 提供的计算时间加速使其对于研究深度过冷水中的缓慢过程、冰成核机制、干湿转变以及作为生物分子和复杂材料的粗粒度模拟的现实水模型特别有用。
Water and silicon are chemically dissimilar substances with common physical properties. Their liquids display a temperature of maximum density, increased diffusivity on compression, and they form tetrahedral crystals and tetrahedral amorphous phases. The common feature to water, silicon, and carbon is the formation of tetrahedrally coordinated units. We exploit these similarities to develop a coarse-grained model of water (mW) that is essentially an atom with tetrahedrality intermediate between carbon and silicon. mW mimics the hydrogen-bonded structure of water through the introduction of a nonbond angular dependent term that encourages tetrahedral configurations. The model departs from the prevailing paradigm in water modeling: the use of long-ranged forces (electrostatics) to produce short-ranged (hydrogen-bonded) structure. mW has only short-range interactions yet it reproduces the energetics, density and structure of liquid water, and its anomalies and phase transitions with comparable or better accuracy than the most popular atomistic models of water, at less than 1% of the computational cost. We conclude that it is not the nature of the interactions but the connectivity of the molecules that determines the structural and thermodynamic behavior of water. The speedup in computing time provided by mW makes it particularly useful for the study of slow processes in deeply supercooled water, the mechanism of ice nucleation, wetting-drying transitions, and as a realistic water model for coarse-grained simulations of biomolecules and complex materials.