Dynamics of Equilibrium Liquids, Supercooled Liquids, and Glasses

汉斯·安徒生由理论和计算化学计划资助，继续他的动力学和平衡的研究，液体，过冷液体和玻璃。Andersen将开发和使用三种类型的统计力学方法来研究致密过冷流体的动力学理论：1)将Martin， Siggia, Rose （MSR）方法的公式应用于粒子和自旋系统的经典动力学；2)致密、低温、微过冷原子液体的分子动力学模拟研究；3)动力学自旋模型的时间依赖性模拟，旨在阐明高度过冷液体和玻璃中的弛豫和结构变化机制。研究的主要目标是：1)提供扩展模耦合理论的推导和准确性的关键测试，并更好地理解该理论的物理内容；2)发展一个运动理论的基础，这是使用投影算子或Mazenko四点函数的替代方案；3)了解如何将挫折限制域的形成、二次弛豫和非均匀弛豫等现象纳入动力学理论。分子动力学模拟将用于研究液体和稍微过冷的状态，更多的图解自旋模型将在较低温度下使用，相关的时间尺度更长。玻璃是一种技术上重要的材料，由多种成分制成，既有有机成分，也有无机成分，既有小分子量物质，也有聚合物。例子包括窗户玻璃和食品容器等普通材料，以及用于电信、光电和固体电解质的高科技材料。作为非平衡材料，它们的性质取决于它们的制备方法，通常包括制备高温液体，然后进行各种冷却和加工步骤。这些材料的制备以达到最佳性能在很大程度上是由经验观察指导的，但安德森的研究寻求在分子水平上理解这些材料及其相应液体的动力学，这对于设计合理的加工程序是有用的。

Hans Andersen is funded by a grant from the Theoretical and Computational Chemistry Program to continue his studies of the dynamics and equilibrium of liquids, supercooled liquids and glasses. Andersen will develop and use three types of statistical mechanical methods for the study of the kinetic theory of dense supercooled fluids: 1) a formulation of the Martin, Siggia, Rose (MSR) approach applied to the classical dynamics of particle and spin systems; 2) molecular dynamics simulation studies of dense, low temperature and slightly supercooled atomic liquids; and 3) simulation of the time dependence of kinetic spin models designed to elucidate mechanisms for relaxation and structural change in highly supercooled liquids and glasses. The major objectives of the research are: 1) to provide critical tests of the derivation and accuracy of the extended mode coupling theory and a greater understanding of the physical content of the theory; 2) to develop a basis for kinetic theory that is an alternative to the use of projection operators or the four-point function of Mazenko; and 3) to understand how to incorporate such phenomena as formation of frustration-limited domains, secondary relaxation, and inhomogeneous relaxation into kinetic theory. Molecular dynamics simulations will be used to study liquids and slightly supercooled regimes, and more schematic spin models will be used at lower temperatures where the relevant time scales are longer. Glasses are technologically important materials made from a variety of components, both organic and inorganic, both small molecular weight substances and polymers. Examples include ordinary materials such as window glass and food containers, as well as high-tech materials for telecommunications, optoelectronics, and solid electrolytes. As nonequilibrium materials, their properties depend on how they are made, which usually involves preparation of a high temperature liquid followed by various cooling and processing steps. The preparation of such materials to achieve optimal performance is guided largely by empirical observations, but Andersen's research seeks an understanding of the dynamics of these materials and their corresponding liquids on a molecular level which can be useful in the design of rational processing procedures.