Anisotropic United Atom Model Including the Electrostatic Interactions of Methylbenzenes. II. Transport Properties

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• 作者：Carlos Nieto-Draghi ; Patrick Bonnaud ; Philippe Ungerer
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：November 1, 2007
• 年：2007
• 卷：111
• 期：43
• 页码：15942 - 15951
• 全文大小：151K
• 年卷期：v.111,no.43(November 1, 2007)
• ISSN：1932-7455

文摘

A new potential model for monoaromatics based an anisotropic united atoms model and three electrostaticcharges is used to simultaneously represent the dipole moments, the vapor-liquid equilibrium, the transportproperties, and the structural properties while keeping computational effort minimal. The present article focuseson the transport properties and dynamic structural properties. Shear viscosities and diffusion coefficients arecomputed from equilibrium molecular dynamics in a large range of pressures (0.1-500 MPa) and temperatures(298-363 K). Viscosity shows a significant improvement with respect to the previous nonpolar models, asaverage deviations on toluene, p-xylene, m-xylene, and o-xylene stay below 9%. Self-diffusion coefficientsand reorientational diffusion coefficients of toluene are also in good agreement with experimental observations.Thermal conductivity, evaluated by nonequilibrium molecular dynamics, reveals maximum deviations of 8%on benzene, toluene, and xylene isomers, which is better than those of other potentials investigated. By itslower computation time and equivalent accuracy compared with all atoms models, the proposed AUA potentialis a good option for investigating complex problems such as the prediction of fuel viscosity in the high-pressure conditions encountered in the injectors of diesel engines.