Normal Mode Analysis of Liquids

波士顿大学的Thomas Keyes得到了理论与计算化学项目的资助，继续他在过冷液体动力学特性的正常模式分析方面的工作。正态分析将用于计算内部振动对二硫化碳和小烷烃中自扩散的影响，液体中模型双原子的振动动力学和寿命，以及正丁烷中的扭转势垒穿越率。这种方法也将用于解释振动寿命的温度依赖性。凯斯计划发展飞秒光谱和溶剂化动力学的理论。理论结果将与分子模拟和实验结果进行比较。有很好的理论模型可以解释运动混乱、碰撞不频繁和相互作用弱的气相系统的行为和性质。固态的理论模型也得到了很好的发展，因为晶体系统中的周期性顺序提供了必要的简化，从而导致易于处理的解决方案。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的挑战。Keyes是几个理论化学家之一，他们在发展液体物理和化学性质的分子解释方面取得了重大进展。这项工作的长期影响可能有助于理解凝聚态化学。

Thomas Keyes of Boston University is supported by a grant from the Theoretical and Computational Chemistry Program to continue his work on normal mode analysis of the dynamical properties of supercooled liquids. Normal mode analysis will be used to calculate the effect of internal vibrations on self diffusion in carbon disulfide and in small alkanes, vibrational dynamics and lifetimes of model diatomics in liquids, and torsional barrier crossing rates in n-butane. This methodology will also be used to interpret the temperature dependence of vibrational lifetimes. Keyes plans to develop a theory for femtosecond spectroscopy and solvation dynamics. Theoretical results will be compared with molecular simulations and with experiment. There are excellent theoretical models which explain the behavior and properties of gas phase systems where the motion is chaotic, collisions infrequent, 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.