Integral equations for simple fluids in a general reference functional approach
Integral equations for simple fluids in a general reference functional approach
复制标题
一般参考函数方法中简单流体的积分方程
DOI：
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
M. Oettel
中科院分区：
文献类型：
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作者：
M. Oettel
利用围绕非均匀平衡分布的自由能的泛函泰勒展开，导出了非均匀流体混合物相关函数的积分方程。该方程组通过引入一个参考泛函来关闭，该泛函用于与平衡分布的密度差中超过二阶的相关性。得到了将流体混合粒子插入非均匀体系所需能量的显式表达式。该方法通过确定一个简单的、截断的Lennard-Jones流体的状态方程和分析该流体在硬壁附近的行为来说明。壁面-流体积分方程显示完全干燥，相应的共存密度与应用于散装流体的标准（麦克斯韦）构造得到的密度很好地一致。通过分析体积流体的状态方程和Gibbs - duhem关系的virv /compressibility路径，以及硬壁问题的接触密度和规则和Gibbs吸附方程，验证了该方法的自一致性。对于整体流体，我们发现临界区域外的稳定状态具有良好的自洽性。对于硬壁问题，吉布斯吸附方程在相共存附近得到很好的满足，此时吸附量较大。对于接触密度求和规则，我们发现本方法预测的接触密度与求和规则预测的接触密度之比的偏差高达20%。这些偏差很大程度上是由于麦克斯韦构造得到的气相共存密度与硬壁完全干燥得到的气相共存密度稍有不同。
The integral equations for the correlation functions of an inhomogeneous fluid mixture are derived using a functional Taylor expansion of the free energy around an inhomogeneous equilibrium distribution. The system of equations is closed by the introduction of a reference functional for the correlations beyond second order in the density difference from the equilibrium distribution. Explicit expressions are obtained for energies required to insert particles of the fluid mixture into the inhomogeneous system. The approach is illustrated by the determination of the equation of state of a simple, truncated Lennard-Jones fluid and the analysis of the behaviour of this fluid near a hard wall. The wall–fluid integral equation exhibits complete drying and the corresponding coexisting densities are in good agreement with those obtained from the standard (Maxwell) construction applied to the bulk fluid. The self-consistency of the approach is examined by analysing the virial/compressibility routes to the equation of state and the Gibbs–Duhem relation for the bulk fluid, and the contact density sum rule and the Gibbs adsorption equation for the hard-wall problem. For the bulk fluid, we find good self-consistency for stable states outside the critical region. For the hard-wall problem, the Gibbs adsorption equation is fulfilled very well near phase coexistence where the adsorption is large. For the contact density sum rule, we find deviations of up to 20% in the ratio of the contact densities predicted by the present method and predicted by the sum rule. These deviations are largely due to a slight disagreement between the coexisting density for the gas phase obtained from the Maxwell construction and from complete drying at the hard wall.
影响因子：
2.4
作者：
Gillespie, D;Nonner, W;Eisenberg, RS
通讯作者：
Eisenberg, RS