SAFT-γ Force Field for the Simulation of Molecular Fluids. 5. Hetero-Group Coarse-Grained Models of Linear Alkanes and the Importance of Intramolecular Interactions.
SAFT-γ Force Field for the Simulation of Molecular Fluids. 5. Hetero-Group Coarse-Grained Models of Linear Alkanes and the Importance of Intramolecular Interactions.
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DOI：
10.1021/acs.jpcb.8b04095
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发表时间：
2018-09
期刊：
影响因子：
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通讯作者：
Sadia Rahman;O. Lobanova;G. Jiménez-Serratos;C. Braga;V. Raptis;E. A. Müller;G. Jackson;C. Avendaño;A. Galindo
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文献类型：
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作者：
Sadia Rahman;O. Lobanova;G. Jiménez-Serratos;C. Braga;V. Raptis;E. A. Müller;G. Jackson;C. Avendaño;A. Galindo
基团贡献状态方程[γJ.太棒了。2014,140,054107]用于开发适用于直链烷烃分子模拟的可转移粗粒(CG)力场。在每个小球的三个碳原子的分辨率下建立了一个杂群模型，其中使用不同的Mie(广义Lennard-Jones)相互作用来表征末端(CH3-CH2-CH2-)和中间(-CH2-)小球。力场是通过结合SAFT-γCG自上而下的方法[Avendaño J.Phys]来开发的。化学。B2011,115,11154]，使用从正庚烷到正十五烷的n-烷烃的实验相平衡数据来参数化分子间(非键)珠-珠相互作用，采用自下而上的方法，依赖于基于更高分辨率的Trappe联合原子(UA)模型的模拟[Martin；，Siepmann J.Phys。化学。B1998,102,2569]以建立分子内(键合)相互作用。SAFT-γCG模型的可转换性是通过详细检查从正己烷(n-C6H14)到正十八烷(n-C18H38)的线性烷烃的性质来评估的，包括对较长链描述的可靠性的额外评估，如正十六烷(n-C60H122)和中等分子量的典型线性聚乙烯(n-C900H1802)。考察了各种结构、热力学和输运性质，包括对分布函数、汽液平衡、界面张力、粘度和扩散系数。特别关注的是纳入分子内相互作用对CG模型的准确性、可转移性和代表性的影响。新的SAFT-γCG力场在大多数情况下提供了对正构烷烃热物理性质的可靠描述，其水平可与更高分辨率模型所获得的水平相媲美。
The SAFT-γ Mie group-contribution equation of state [ Papaioannou J. Chem. Phys. 2014 , 140 , 054107 ] is used to develop a transferable coarse-grained (CG) force-field suitable for the molecular simulation of linear alkanes. A heterogroup model is fashioned at the resolution of three carbon atoms per bead in which different Mie (generalized Lennard-Jones) interactions are used to characterize the terminal (CH3-CH2-CH2-) and middle (-CH2-CH2-CH2-) beads. The force field is developed by combining the SAFT-γ CG top-down approach [ Avendaño J. Phys. Chem. B 2011 , 115 , 11154 ], using experimental phase-equilibrium data for n-alkanes ranging from n-nonane to n-pentadecane to parametrize the intermolecular (nonbonded) bead-bead interactions, with a bottom-up approach relying on simulations based on the higher resolution TraPPE united-atom (UA) model [ Martin ; , Siepmann J. Phys. Chem. B 1998 , 102 , 2569 ] to establish the intramolecular (bonded) interactions. The transferability of the SAFT-γ CG model is assessed from a detailed examination of the properties of linear alkanes ranging from n-hexane ( n-C6H14) to n-octadecane ( n-C18H38), including an additional evaluation of the reliability of the description for longer chains such as n-hexacontane ( n-C60H122) and a prototypical linear polyethylene of moderate molecular weight ( n-C900H1802). A variety of structural, thermodynamic, and transport properties are examined, including the pair distribution functions, vapor-liquid equilibria, interfacial tension, viscosity, and diffusivity. Particular focus is placed on the impact of incorporating intramolecular interactions on the accuracy, transferability, and representability of the CG model. The novel SAFT-γ CG force field is shown to provide a reliable description of the thermophysical properties of the n-alkanes, in most cases at a level comparable to the that obtained with higher resolution models.