SAFT-γ Force Field for the Simulation of Molecular Fluids. 1. A Single-Site Coarse Grained Model of Carbon Dioxide

Abstract

An application of the "top-down" concept for the development of accurate coarse-grained intermolecular potentials of complex fluids is presented. With the more common "bottomup" procedure, coarse-grained models are constructed from a suitable simplification of a fulldetailed atomistic representation, and minor adjustments to the intermolecular parameters are made by comparison with limited experimental data where necessary. By contrast in the top-down approach, a molecular-based equation of state is used to obtain an effective coarsegrained intermolecular potential that reproduces the macroscopic experimental thermophysical properties over a wide range of conditions. These coarse-grained intermolecular potentials can then be used in a conventional molecular simulation to obtain properties (such as structure or dynamics) that are not directly accessible from the equation of state or at extreme conditions where the theory is expected to fail. In order to demonstrate our procedure, a coarse-

High-pressure densities and interfacial tensions of binary systems containing carbon dioxide+n-alkanes: (n-Dodecane, n-tridecane, n-tetradecane)

“…In this work, bulk phase mass densities and interfacial tension of CO 2 + n-alkane (n-C 12 H 26 or n-C 13 a Pure n-alkane parameters of the SAFT-VR-Mie EoS have been taken from Mejía et al [78], and from Avendaño et al [79] for CO 2 . c i were fitted from experimental γ data which have been taken from NIST-REFPROP data base [58] Experimental data taken from: a.…”

“…In this work we modeled CO 2 as a single sphere [79]; n-C 12 H 26 and n-C 13 H 28 are formed by three tangential spheres whereas n-C 14 H 30 is represented using four tangential spheres [78]. These tangential spheres interact each other through the Mie potential (see Eq.…”

Understanding and Describing the Liquid-Crystalline States of Polypeptide Solutions: A Coarse-Grained Model of PBLG in DMF

“…132,133 The SAFT equation of state has recently been employed to develop coarse-grained force fields for direct use in molecular simulation. [134][135][136] In future work we plan to take advantage of these developments and improve our model and theoretical approach to provide a predictive platform for the the phase behaviour of thermotropic liquid crystals as well as the structures of the corresponding anisotropic phases. …”

Modelling the interfacial behaviour of dilute light-switching surfactant solutions

“…More details about the CG procedure may be found elsewhere. [45][46][47] The Mie potential in equation (6) may expressed in terms of two constants A and C that consolidate all the functionality corresponding to the prefactor, and the size and energy parameters. This functional form, expressed in the right hand side of equation (6) is commonly used when tabulating potentials in MD codes.…”