Dynamics of Equilibrium Liquids, Supercooled Liquids, and Glasses

平衡液体、过冷液体和玻璃的动力学

• 批准号: 0010117
• 负责人: Hans Andersen
• 金额: $ 53.64万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0010117&HistoricalAwards=false
• 关键词: Dynamics; Equilibrium; Liquids; Supercooled; Glasses

Hans Andersen of Stanford University is supported by the Theoretical and Computational Chemistry Program to continue development of theoretical methods to calculate dynamical properties of liquids, supercooled liquids, and glasses at the molecular level. The basic strategy is to use a formally exact theory to create approximate kinetic theories of liquids, and then perform molecular dynamics computer simulations to test the accuracy of these approximations. Practical and accurate approximations capable of describing important physical processes that take place in low temperature liquids will be developed through this research. The specific objectives of this project include: (1) understanding and describing quantitatively the change that occurs in the dynamics of molecules as a liquid material is cooled and molecules become trapped for an extended period of time in a "cage" formed by its neighbors, (2) developing an understanding of how structural changes that take place in supercooled liquids can affect the dynamics, (3) understanding the variety of relaxation processes that take place and the relationships among them, and ultimately (4) understanding the very slow relaxation processes at very low temperature that lead to the formation of a glass at the glass transition. Glasses are technologically important materials made from a variety of components, both organic and inorganic, both low molecular weights substances and polymers. Examples include ordinary materials such as window glass and food containers, as well as advanced materials such as fiber optics for telecommunications, optical electronics, and solid electrolytes. The properties of these materials depend on how they are made, using methods that usually involves preparation of a high temperature liquids followed by various cooling and processing steps. The creation of optimal performance materials is currently guided largely by empirical observations. Design of rational processing procedures is expected to be enhanced by the increased understanding of dynamics of these materials and their corresponding liquids that will emerge from this research effort.

斯坦福大学的Hans Andersen得到了理论和计算化学项目的支持，继续发展理论方法来计算分子水平上液体、过冷液体和玻璃的动力学性质。 基本策略是使用形式上精确的理论来创建近似的液体动力学理论，然后进行分子动力学计算机模拟来测试这些近似的准确性。 通过这项研究，将开发出能够描述低温液体中发生的重要物理过程的实用和准确的近似方法。 该项目的具体目标包括：（1）理解和定量描述当液体材料被冷却并且分子被困在由其邻居形成的“笼”中一段延长的时间时分子动力学中发生的变化，（2）理解在过冷液体中发生的结构变化如何影响动力学，（3）理解发生的各种弛豫过程以及它们之间的关系，最终（4）理解在非常低的温度下导致在玻璃化转变时形成玻璃的非常缓慢的弛豫过程。 玻璃是一种重要的技术材料，由各种成分制成，包括有机和无机，低分子量物质和聚合物。 例子包括普通材料，如窗玻璃和食品容器，以及先进的材料，如光纤电信，光学电子和固体电解质。 这些材料的特性取决于它们是如何制造的，使用的方法通常涉及制备高温液体，然后进行各种冷却和加工步骤。 目前，最佳性能材料的创建主要是由经验观察指导的。 合理的处理程序的设计，预计将得到加强，这些材料和相应的液体，将出现从这项研究工作的动力学的理解。