Zhou Shiqi, Sun Hongwei
Research Institute of Modern Statistical Mechanics, Zhuzhou Institute of Technology, Wenhua Road, Zhuzhou City 412008, P. R. China.
J Phys Chem B. 2005 Apr 7;109(13):6397-404. doi: 10.1021/jp0462512.
The sedimentation equilibrium of colloidal suspensions modeled by hard-core attractive Yukawa (HCAY) fluids in a planar pore is studied. The density profile of the HCAY fluid in a gravitational field and its distribution between the pore and uniform phases are investigated by a density functional theory (DFT) approach, which results from employing a recently proposed parameter-free version of the Lagrangian theorem-based density functional approximation (Zhou, S. Phys. Lett. A 2003, 319, 279) for hard-sphere fluids to the hard-core part of the HCAY fluid, and the second-order functional perturbation expansion approximation to the tail part as was done in a recent partitioned density functional approximation (Zhou, S. Phys. Rev. E: Stat. Phys., Plasmas, Fluids, Relat. Interdiscip. Top. 2003, 68, 061201). The resultant DFT approach is, thus, the first adjustable parameter-free DFT for HCAY fluids. The validity of the present DFT for HCAY fluids of reduced range parameter z(red) = 1.8 under various external potentials is established in the first of the papers cited previously. The present DFT for HCAY fluids can predict the radial distribution function for the bulk HCAY fluid accurately in the colloidal limit (large value of z(red)), and in the hard-sphere limit, its prediction for the density profile of the hard-sphere fluid in a gravitational field is in very good agreement with the existing simulation data. The dependence of the density profile and distribution coefficient on the magnitude of the interparticle attraction, gravitational field, and degree of confinement is investigated in detail by the present DFT approach. Intuitive and qualitative analyses are also compared with the quantitative DFT calculational results.
研究了由平面孔中硬核吸引 Yukawa（HCAY）流体模拟的胶体悬浮液的沉降平衡。通过密度泛函理论（DFT）方法研究了重力场中 HCAY 流体的密度分布及其在孔相和均匀相之间的分布，该方法是将最近提出的基于拉格朗日定理的无参数密度泛函近似（Zhou，S. Phys. Lett. A 2003，319，279）用于硬球流体的硬核部分，并将二阶泛函微扰展开近似用于尾部部分，就像最近的分区密度泛函近似（Zhou，S. Phys. Rev. E：Stat. Phys., Plasmas, Fluids, Relat. Interdiscip. Top. 2003，68，061201）那样。因此，所得的 DFT 方法是首个用于 HCAY 流体的无可调参数的 DFT。在前面引用的第一篇论文中确定了当前针对约化范围参数 z(red) = 1.8 的 HCAY 流体在各种外部势下的 DFT 的有效性。当前用于 HCAY 流体的 DFT 能够在胶体极限（z(red) 较大值）下准确预测本体 HCAY 流体的径向分布函数，并且在硬球极限下，其对重力场中硬球流体密度分布的预测与现有模拟数据非常吻合。通过当前的 DFT 方法详细研究了密度分布和分配系数对粒子间吸引力大小、重力场和限制程度的依赖性。还将直观和定性分析与定量的 DFT 计算结果进行了比较。
