Coarse-Graining of TIP4P/2005, TIP4P-Ew, SPC/E, and TIP3P to Monatomic Anisotropic Water Models Using Relative Entropy Minimization

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• 作者：Jibao Lu ; Yuqing Qiu ; Riccardo Baron ; Valeria Molinero
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2014
• 出版时间：September 9, 2014
• 年：2014
• 卷：10
• 期：9
• 页码：4104-4120
• 全文大小：679K
• ISSN：1549-9626

文摘

Coarse-grained models are becoming a competitive alternative for modeling processes that occur over time and length scales beyond the reach of fully atomistic molecular simulations. Ideally, coarse-grained models should not only achieve high computational efficiency but also provide accurate predictions and fundamental insight into the role of molecular interactions, the characteristic behavior, and properties of the system they model. In this work we derive a series of monatomic coarse-grained water models mX^REM from the most popular atomistic water models X = TIP3P, SPC/E, TIP4P-Ew, and TIP4P/2005, using the relative entropy minimization (REM) method. Each coarse-grained water molecule is represented by a single particle that interacts through short-ranged anisotropic interactions that encourage the formation of 鈥渉ydrogen-bonded鈥?structures. We systematically investigate the features of the coarse-grained models in reproducing over 20 structural, dynamic, and thermodynamic properties of the reference atomistic water models鈥攊ncluding the existence and locus of the characteristic density anomaly. The mX^REM coarse-grained models reproduce quite faithfully the radial and angular distribution function of water, produce a temperature of maximum density (TMD), and stabilize the ice I crystal. Moreover, the ratio between the TMD and the melting temperature of the crystal in the mX^REM models and liquid鈥搃ce equilibrium properties show reasonable agreement with the results of the corresponding atomistic models. The mX^REM models, however, severely underestimate the cohesive energy of the condensed water phases. We investigate which specific limitations of the coarse-grained models arise from the REM methodology, from the monatomic nature of the models, and from the Stillinger鈥揥eber interaction potential form. Our analysis indicates that a small compromise in the accuracy of structural properties can result in a significant increase of the overall accuracy and representability of the coarse-grained water models. We evaluate the accuracy of the atomistic and the monatomic anisotropic coarse-grained water models, including the mW water model, in reproducing experimental water properties. We find that mW and mTIP4P/2005^REM score closer to experiment than widely used atomistic water models. We conclude that monatomic models of water with short-range, anisotropic 鈥渉ydrogen-bonding鈥?three-body interactions can be competitive in accuracy with fully atomistic models for the study of a wide range of properties and phenomena at less than 1/100th of the computational cost.