A computational investigation of thermodynamics, structure, dynamics and solvation behavior in modified water models
A computational investigation of thermodynamics, structure, dynamics and solvation behavior in modified water models
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DOI：
10.1063/1.2841127
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发表时间：
2008-03-28
影响因子：
4.4
通讯作者：
Lynden-Bell, Ruth M.
中科院分区：
文献类型：
--
作者：
Chatterjee, Swaroop;Debenedetti, Pablo G.;Lynden-Bell, Ruth M.
我们通过对水的扩展简单点电荷（SPC/E）模型在1 bar的宽温度范围内的扰动进行分子动力学模拟来研究几何修正水模型的性质。几何修饰包括改变SPC/E的H-O-H角。通过改变O-H键的长度，偶极矩保持不变，而静电荷保持不变。我们发现，至少100度的H-O-H角对于小极性溶质的密度异常和溶解度极值的出现是必要的。我们观察到在这些模型中出现了两种不相容的结构顺序：四面体，对于H-O-H角超过100度的弯曲模型具有类似水的平移顺序；对于较小的H-O-H角，具有类似lennard - jones的方向平均平动顺序。增加H-O-H角导致密度增加，同时将水样异常转移到逐渐升高的温度。对于H-O-H角大于SPC/E的弯曲模型，我们观察到在300 K（115度）和330 K（120度）时平移运动停止。(C) 2008年美国物理研究所。
We investigate the properties of geometrically modified water models by performing molecular dynamics simulations of perturbations of the extended simple point charge (SPC/E) model of water over a wide range of temperatures at 1 bar. The geometric modification consists of altering the H-O-H angle in SPC/E. The dipole moment is held constant by altering the O-H bond length, while the electrostatic charges are left unchanged. We find that a H-O-H angle of at least 100 degrees is necessary for the appearance of density anomalies and of solubility extrema with respect to temperature for small apolar solutes. We observe the occurrence of two incompatible types of structural order in these models: Tetrahedral, with waterlike translational order for bent models with H-O-H angles in excess of 100 degrees; and linear, with Lennard-Jones-like orientationally averaged translational order for smaller H-O-H angles. Increasing the H-O-H angle causes the density to increase, while at the same time shifting waterlike anomalies to progressively higher temperatures. For bent models with H-O-H angle greater than SPC/E's, we observe arrest of translational motion at 300 K (115 degrees) and 330 K (120 degrees). (C) 2008 American Institute of Physics.