Instantaneous Normal Mode Analysis of Liquids

托马斯凯斯得到了理论和 计算化学计划，继续他在该领域的研究 液体的瞬时简正波分析。 瞬时 简正模式是具有代表性的配置的谐波模式， 液体，它们提供了对液体状态的直观描述， 动力学 凯斯将进一步发展INM理论，以治疗放松， 过冷液体 自扩散常数将由下式计算： 双势阱模式和强、弱势的不同行为 过冷液体将与双阱的形式有关 态密度 过冷液体的其他性质，包括 散射中的玻色子峰值，一个可能增长的相关长度， 相关函数的拉伸指数衰减， 斯托克斯-爱因斯坦定律，以及空间异质性的作用 从INM计算。 当前理论的扩展将是 研究引入含时绝热和非绝热法线 模式治疗。 这将把INM治疗扩展到失相， 动态缩小 有很好的理论模型可以解释这种行为， 运动是混沌的气相系统的性质， 频繁，相互作用很弱。固体的理论模型 由于晶体中周期性排列， 系统提供了必要的简化， 解决方案液体和过冷液体或玻璃的性质 仍然对理论解释提出了相当大挑战。 Keyes是 他是几位理论化学家之一， 从分子角度解释了 液体的性质。这项工作的长期影响可能是 有助于理解凝聚态化学。

Thomas Keyes is supported by a grant from the Theoretical and Computational Chemistry Program to continue his research in the area of instantaneous normal mode (INM) analysis of liquids. Instantaneous normal modes are the harmonic modes of a representative configuration of a liquid, and they provide an intuitive description of liquid state dynamics. Keyes will further develop INM theory to treat relaxation in supercooled liquids. The self diffusion constant will be calculated from the double well modes and the distinct behavior of strong and fragile supercooled liquids will be related to the form of the double well density of states. Other properties of supercooled liquids including the Boson peak in scattering, a possible growing correlation length, stretched exponential decay of correlation functions, breakdown in the Stokes-Einstein law, and the role of spatial heterogeneity will be calculated from INM. An extension of the current theory will be investigated to introduce time-dependent adiabatic and diabatic normal mode treatments. This would extend the INM treatment to dephasing and motional narrowing. There are excellent theoretical models which explain the behavior and properties of gas phase systems where the motion is chaotic, collisions frequent, and interactions are weak. Theoretical models for the solid state are also quite well developed since periodic order in crystalline systems provides the necessary simplifications to lead to tractable solutions. The properties of liquids and supercooled liquids or glasses still present quite a challenge to theoretical interpretation. Keyes is one of several theoretical chemists who is making significant headway on developing a molecular interpretation of the physical and chemical properties of liquids. The long range impact of this work could be significant in helping to understand chemistry in condensed phases.