Theory of Inhomogeneous and Confined Fluids

约翰·威克斯教授得到了理论和计算化学项目的资助，用于研究非均质和受限流体的理论。威克斯将使用一种新颖的、具有物理意义的方法来处理不均匀的流体，这种方法以一种自洽的方式结合了吸引力的平均场处理和可能精确的排斥力关联处理。该方法产生一种非均匀排斥力参考流体，其结构近似于完整系统的结构。这项研究的第二个主要主题概括了大卫·钱德勒关于液体密度波动的高斯场理论的工作，其中考虑了排除的体积效应。这允许一种新的和物理激励的方法来推导重要的积分方程类。建议的应用包括在壁上的湿润和干燥效应，在狭缝孔和纳米管中的吸附，聚合物，以及自由液-汽界面。本研究将采用解析理论和计算机模拟相结合的方法。实验表明，非均匀流体的静态和动态性质，特别是当被限制在小孔或缝隙中时，都与均匀体系的性质有很大不同。需要新的理论思想来帮助理解这些令人惊讶的结果，这些结果影响了化学、物理和流体力学的一些基础研究领域。此外，这些想法可能在涉及润滑、摩擦和磨损的材料加工操作中具有实际应用。

Professor John Weeks is supported by a grant from the Theoretical and Computational Chemistry Program to study the theory of inhomogeneous and confined fluids. Weeks will use a novel and physically suggestive method for treating nonuniform fluids that combines, in a self-consistent way, a mean field treatment of the attractive forces with a potentially exact treatment of the repulsive force correlations. The method yields a nonuniform repulsive force reference fluid whose structure approximates that of the full system. A second major theme of the research generalizes the work by David Chandler on a Gaussian field theory for density fluctuations in liquids, where excluded volume effects are taken into account. This allows a new and physically motivated way of deriving important classes of integral equations. Proposed applications include wetting and drying effects at walls, adsorption in slit pores and nanotubes, polymers, and the free liquid-vapor interface. Both analytical theory and computer simulations will be employed in this research. Experiments have shown that both the static and dynamic properties of nonuniform fluids, particularly when confined in small pores or slits, differ dramatically from those of uniform systems. New theoretical ideas are needed to help make sense of these surprising results that impact on a number of basic research areas in chemistry, physics, and fluid mechanics. In addition, these ideas could have practical applications to materials processing operations involving lubrication, friction and wear.