Molecular Dynamics Simulations of Quinoline in the Liquid Phase

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• 作者：Jean-Christophe Soetens ; Norariza Ahmad ; Rohana Adnan ; Claude Millot
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：May 17, 2012
• 年：2012
• 卷：116
• 期：19
• 页码：5719-5728
• 全文大小：423K
• 年卷期：v.116,no.19(May 17, 2012)
• ISSN：1520-5207

文摘

Molecular dynamics simulations of liquid quinoline have been performed at experimental densities corresponding to the temperature range 276鈥?20 K. The intermolecular potential is a simple effective two-body potential between rigid molecules having 17 atomic Lennard-Jones and electrostatic Coulomb interaction sites. The vaporization enthalpy is overestimated by 8鈥?% with respect to the experimental value. The translational diffusion coefficient exhibits a small non-Arrhenius behavior with a change in temperatures near 290 and 303 K. The rotational diffusion tensor is rotated around the z axis perpendicular to the molecular plane by an angle of 4鈥?掳 with respect to the frame of reference defined by the principal axes of inertia. The rotational diffusion tensor presents a significant anisotropy with D_rot,y/D_rot,x 0.6鈥?.5 and D_rot,z/D_rot,x 1.6鈥?.3 between 276 and 320 K when the x axis is defined as the long molecular axis and the y axis is situated nearly along the central C鈥揅 bond. The rotational diffusion coefficients, the reorientational correlation times of the C鈥揌 vectors, and the T₁¹³C NMR relaxation times present a non-Arrhenius break around 288鈥?90 K in agreement with several experimental results. In addition, a non-Arrhenius break can also be observed at 303 K for these properties. It has been found that the structure evolves smoothly in the studied temperature range. Center of mass鈥揷enter of mass and atom鈥揳tom radial distribution functions show a monotonous evolution with temperature. Various types of first-neighbor dimers have been defined, and their population analysis has revealed a continuous monotonous evolution with temperature. Thus, the non-Arrhenius behavior observed for translational and rotational diffusion is correlated with the monotonous evolution of the population of first-neighbor dimers at a microscopic level and not with a sharp structural transition.