从蒙特卡洛模拟和Onsager理论重新审视狭缝几何中HGO系统在二维和三维情况下的取向性质
Orientational properties of the HGO system in a slit geometry in two-dimensional and three-dimensional case from Monte Carlo simulations and Onsager theory revisited
AI总结：
本文结合Onsager型DFT和蒙特卡洛模拟，研究狭缝中二维与三维HGO椭球体的取向和密度结构，揭示三维中平面与垂直排列的双稳态特征值交换现象，并分析壁面穿透性对结果的影响。
摘要：
利用密度泛函理论（DFT）的Onsager型第二维里近似和恒压蒙特卡洛（MC）模拟，重新审视了受限三维（3D）和二维（2D）硬高斯重叠（HGO）椭球体的取向与密度结构性质问题。在壁面处，三维中被假设的粒子被迫表现出平面排列。在向列相以及近晶相区域中，远离壁面的粒子呈现垂直排列。这种不寻常的双稳态重排被称为序参数张量的特征值交换问题。同时，在同一系统的二维情形中未观察到双稳态排列。文中给出了DFT理论与MC模拟结果的比较。尽管在较大密度范围内，由MC模拟和DFT理论得到的取向性质的比较是合理的，但这并不适用于密度分布。在较稠密的系统中差异变得更大。然而，结果表明，通过调控壁面处粒子的可穿透程度，可以影响表面密度，从而改善比较结果。文中还讨论了哪些因素促进受限环境中平面排列与垂直排列同时存在的问题。
英文摘要：
A problem of the orientational and density structure properties of a confined three-dimensional (3D) and two-dimensional (2D) Hard Gausssian Overlap (HGO) ellipsoids has been revisited using the Onsager-type second virial approximation of Density Functional Theory (DFT) and constant-pressure Monte-Carlo (MC) simulations. At the walls the asssumed particles in 3D are forced to exhibit planar alignment. In the nematic as well as in the smectic regime particles situated apart from the walls attain homeotropic arrangement. This unusual bistable rearrangement is named as the eigenvalue exchange problem of the order parameter tensor. At the same time a bistable arrangement is not observed in the two-dimensional case of the same system. Comparison of the DFT theory and MC simulation results has been given. Whereas comparison of the orientational properties obtained from MC simulations and DFT theory is reasonable for a large range of densities, it does not concern the density profiles. In denser systems differences become larger. It occurred, however, that by manipulating degree of penetrability of the particles at the walls one can influence the surfacial density which improves comparison. A discussion upon the problem what factors promote simultaneous existence of planar and homeotropic arrangement in a confinement has been provided.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
