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
File(s)Rahman et al Revised JPCB.pdf (1.93 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
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.
Date Issued
2018-09-04
Date Acceptance
2018-09-04
Citation
Journal of Physical Chemistry B, 2018, 122 (39), pp.9161-9177
ISSN
1520-5207
Publisher
American Chemical Society
Start Page
9161
End Page
9177
Journal / Book Title
Journal of Physical Chemistry B
Volume
122
Issue
39
Copyright Statement
© 2018 American Chemical Society
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/E016340/1
EP/J014958/1
Subjects
Science & Technology
Physical Sciences
Chemistry, Physical
Chemistry
EQUATION-OF-STATE
DIRECTIONAL ATTRACTIVE FORCES
THERMODYNAMIC PERTURBATION-THEORY
VAPOR-LIQUID-EQUILIBRIA
N-ALKANES
DYNAMICS SIMULATIONS
TRANSPORT-PROPERTIES
PHASE-EQUILIBRIA
INTERMOLECULAR POTENTIALS
DIFFUSION-COEFFICIENTS
03 Chemical Sciences
09 Engineering
02 Physical Sciences
Publication Status
Published