A new scheme for perturbation contribution in density functional theory and application to solvation force and critical fluctuations.
A new scheme for perturbation contribution in density functional theory and application to solvation force and critical fluctuations.
复制标题
DOI：
10.1063/1.3242717
复制
发表时间：
2009-10
期刊：
影响因子：
--
通讯作者：
Shiqi Zhou
中科院分区：
文献类型：
--
作者：
Shiqi Zhou
为了克服传统的平均场密度泛函近似对液态粒子间势函数微扰项的处理，采用加权密度近似引入关联项来处理平均场之外的微扰自由能.因此，自由能密度泛函近似是先进的平均场项和相关项与硬球项处理与拉格朗日定理为基础的密度泛函近似在本工作中。目前的自由能密度泛函近似的经典密度泛函理论（DFT）的框架内施加到硬核吸引Yukawa（HCAY）流体受到外部领域的比较，所得的预测密度分布与可用的模拟数据是有利的，目前的DFT方法作为一个高度准确的预测方法。然后，采用密度泛函方法研究了两个无限大的平面之间的溶剂化力的影响因素与HCAY势函数的干预溶剂。结果表明：（1）临界涨落引起负吸附和长程溶剂化力，（2）对于窄缝，外电势范围的影响较小，而外场接触电势的强度起主导作用;（iii）体相图中的状态点，其中显示最显著的临界效应，是具有比临界密度稍高的堆积密度的一个;临界波动的残余物保持接近于体积气-液共存曲线。
To surpass a traditional mean field density functional approximation for a perturbation term of interparticle potential function in liquid state, a correlation term is introduced by using weighted density approximation to deal with the perturbation free energy beyond the mean field one. Consequently, a free energy density functional approximation is advanced by combining the mean field term and correlation term with a hard sphere term treated with a Lagrangian theorem-based density functional approximation in the present work. The present free energy density functional approximation is applied in the framework of classical density functional theory (DFT) to a hard core attractive Yukawa (HCAY) fluid subject to external fields; comparison of the resulted predictions for density profiles with available simulation data is favorable for the present DFT approach as a highly accurate predictive approach. Then, the DFT approach is employed to investigate influencing factors for solvation forces between two infinite planar surfaces immersed in an intervening solvent with the HCAY potential function. It is found that (i) critical fluctuations induce negative adsorptions and long-ranged solvation forces; (ii) for narrow slit, the effect of external potential range is kept down; instead strength of the external field contact potential plays dominating role; (iii) state point in the bulk phase diagram, where the most remarkable critical effects are displayed, is the one with a bulk density a little higher than the critical density; remnants of critical fluctuations remain close to the bulk gas-liquid coexistence curve.