Lutsko James F
Physics Department CP 231, Université Libre de Bruxelles, Blvd. du Triomphe, Brussels, Belgium.
J Chem Phys. 2008 May 14;128(18):184711. doi: 10.1063/1.2916694.
Previously, it has been shown that the direct correlation function for a Lennard-Jones fluid could be modeled by a sum of that for hard-spheres, a mean-field tail, and a simple linear correction in the core region constructed so as to reproduce the (known) bulk equation of state of the fluid [Lutsko, J. Chem. Phys. 127, 054701 (2007)]. Here, this model is combined with ideas from the fundamental measure theory to construct a density functional theory for the free energy. The theory is shown to accurately describe a range of inhomogeneous conditions including the liquid vapor interface, the fluid in contact with a hard wall, and a fluid confined in a slit pore. The theory gives quantitatively accurate predictions for the surface tension, including its dependence on the potential cutoff. It also obeys two important exact conditions: That relating the direct correlation function to the functional derivative of the free energy with respect to density and the wall theorem.
此前已经表明，对于 Lennard-Jones 流体，其直接相关函数可以通过硬球流体的直接相关函数、平均场尾部以及在核心区域的一个简单线性校正之和来建模，该线性校正的构建是为了重现（已知的）流体体相状态方程 [Lutsko, J. Chem. Phys. 127, 054701 (2007)]。在此，该模型与基本度量理论的思想相结合，构建了一个关于自由能的密度泛函理论。结果表明，该理论能够准确描述一系列非均匀条件，包括液 - 气界面、与硬壁接触的流体以及限制在狭缝孔中的流体。该理论对表面张力给出了定量准确的预测，包括其对势截止的依赖性。它还满足两个重要的精确条件：一个是将直接相关函数与自由能关于密度的泛函导数联系起来的条件，另一个是壁定理。
