Large-Scale Simulations of Liquid Crystals

这笔赠款将支持使用最先进的计算机对液晶进行理论和计算研究。液晶是一种迷人的材料，其性质介于固体和液体之间。它们对显示设备等技术应用非常重要，而层状液晶结构与脂质双层的生物学研究有关。液晶研究中的一个突出问题是分子结构如何影响观察到的宏观行为。尽管存在这种联系背后的经验规则，但人们对此的基本理解有限。本研究试图通过数值模拟来提高我们的理解。我们将对各种液晶模型进行大规模的数值模拟。这项工作中将要开发和使用的模型本质上是唯象的，即它们不包括原子水平的细节，但确实包括基本的分子特征，如形状、电子多极矩以及吸引和排斥分子间相互作用的相对强度。通过考虑唯象模型而不是原子模型，可以模拟更大的系统。我们将研究各种物理现象，包括：挠曲电性(液晶对取向形变的电学响应)，由非手性模型形成的手性液晶相，近晶相中分子倾斜的机制，向列相中的拓扑缺陷的性质，以及受限向列相的性质。模拟技术将包括分子动力学和蒙特卡罗算法。模拟将在位于圣地亚哥超级计算中心的工作站和大规模并行Cray计算机上进行。这项研究旨在了解液晶的性质。液晶是介于固体和液体之间的令人着迷的材料，也就是说，它们都有各自的性质。液晶通常用于手表和计算机屏幕的显示目的。许多生物系统都处于液晶状态。这个项目使用最先进的计算机来模拟各种类型的液晶的行为。除了提供对液晶的更深层次的理解外，这些结果对于应用也应该是非常有意义的。这个小组在模拟这些复杂系统方面具有独特的能力。***

9873849PelcovitsThis grant will support theoretical and computational research on liquid crystals using state of the art computers. Liquid crystals are fascinating materials with properties intermediate between those of solids and liquids. They are important for technological applications such as display devices, and layered liquid crystalline structures are relevant to biological research on lipid bilayers. An outstanding question in liquid crystal research is how molecular structure influences observed macroscopic behavior. While there are empirical rules underlying this connection, there is limited fundamental understanding. This research attempts to improve our understanding through numerical simulations.Large-scale numerical simulations of a variety of models of liquid crystals will be carried out. The models to be developed and used in this work are phenomenological in nature, i.e., they do not include atomic-level detail, but do include the essential molecular features such as shape, electric multipole moments, and the relative strengths of attractive and repulsive intermolecular interactions. By considering phenomenological as opposed to atomistic models, larger systems can be simulated. A variety of physical phenomena will be studied including: flexoelectricity (the electrical response of a liquid crystal to an orientational deformation), the formation of chiral liquid crystal phases from achiral moelcules, the mechanism underlying molecular tilt in smectic phases, the properties of topological defects in nematics, and the properties of confined nematics. Simulation techniques will include molecular dynamics and Monte Carlo algorithms. The simulations will be carried out on workstations and massively parallel Cray computers located at the San Diego Supercomputing Center.%%%This research is aimed at understanding the properties of liquid crystals. Liquid crystals are fascinating materials which are intermediate between solids and liquids, that is, they have properties of each. Liquid crystals are commonly used for display purposes in watches and computer screens. Many biological systems are in a liquid crystal state. This project uses state of the art computers to simulate the behavior of various types of liquid crystals. Besides providing a deeper understanding of liquid crystals, the results should be of great interest for applications. This group has a unique capability for simulating these complex systems. ***