【作者】 夏志强；

【导师】 仲崇立；

【作者基本信息】 北京化工大学 ， 化学工程， 2006， 硕士

【摘要】 近年来，密度泛函理论(DFT)成为研究非均匀流体的结构和热力学性质广为采用的理论方法。本文应用密度泛函理论对流体界面的结构、热力学性质进行了广泛研究。本文结合改进的基本度量理论(MFMT)与一阶平均球近似(FMSA)理论解析得到的径向分布函数(RDF)和直接相关函数(DCF)建立了密度泛函理论框架，并在其展开项中考虑了高阶微扰项作用，即考虑了主体流体密度不一致性，以避免在计算界面密度分布时出现难以收敛、误差大等问题。其中的相平衡性质以及密度泛函理论中的直接相关函数的计算均系统地来自于FMSA。通过采用MFMT和高阶FMSA展开分别表示硬球排斥和色散吸引作用对Helmholtz自由能泛函的贡献，得到了LJ流体的密度泛函方法。由理论计算得到了不同温度下流体的界面密度分布、界面张力，计算表明理论预测和MC模拟结果符合的很好。将高阶展开扩展应用到缔合流体，理论成功地预测了缔合流体地界面分布、界面张力，较之原有的密度泛函方法均有了明显改善，通过与MC模拟结果比较表明该方法对缔合流体也是非常准确和有效的。进而，本文对链节单体间含有吸引作用的链状流体的界面结构性质进行了探索性研究，为我们进一步深入研究聚合物流体界面性质奠定了坚实的基础。更多还原

【Abstract】 In recent years, density functional theory (DFT) has been employed to obtain the structure properties and the thermodynamics properties of inhomogeneous fluids extensively. In this thesis, DFT is used to study the fluid’s configuration properties and thermodynamic properties.The analytical radial distribution function and the direct correlation function which are obtained from the FMSA, together with MFMT, are applied to construct the density functional theory. In order to recover the bulk vapor and liquid densities of the Lennard-Jones fluid, the high-order terms of FMSA are included into the DFT to replace the ordinary second-order expansion. The computations of all phase equilibrium properties and direct correlation function for DFT are developed systematically from FMSA.We arrived at the DFT for Lennard-Jones fluid by constructing the excess free energy with MFMT and high-order FMSA. We employ this DFT to study the density profile and surface tension at various temperatures. The method was extended to the associating fluid. The calculated density profiles and interfacial tension are much better than those from ordinary DFT. The results indicates that our theory can capture the character of the associating fluid when compared with molecular simulation data. Furthermore, we do an exploringly research on the interfacial properties of chainlike fluid with attraction. This DFT is a useful theoretic tool for our future study on the interfacial properties of polymeric fluid.更多还原