Dynamics and Structure of Polyatomic Fluids

在这个物理化学项目的理论和计算化学子项目中，Evans将研究多原子分子的硬光滑凸体（HCB）模型的分子间结构和动力学理论。该项目的总体主题是了解最简单模型的预测，可以作为未来工作的参考系统。在一个与自扩散有关的项目中，目的是分析笼化与动量反馈回忆对致密流体中非球形分子的平移和旋转动力学的影响。HCB模型已应用于气相反应动力学，它成功地解释了定向分子反应中横截面上的空间效应。计划包括扩展这一模型，以纳入化学反应中的能源瓶颈。当HCB模型应用于分析液体的结构秩序时，它预测溶剂如何围绕溶质排列。这项工作将扩展到分析非球形分子液体中的长程和短程取向顺序。目前的分析理论，结合对完全相同系统的计算机模拟，提供了对多原子分子流体性质的清晰观察。

In this project in the Theoretical and Computational Chemistry Subprogram of the Physical Chemistry Program, Evans will work on the theory of the intermolecular structure and dynamics of a hard smooth convex body (HCB) model of polyatomic molecules. The overall theme of the project is to understand the predictions of the simplest model that can serve as a reference system for future work. In one project pertaining to self diffusion the aim is to analyze the effects of caging versus momentum feedback recollisions on the translational and rotational dynamics of nonspherical molecules in dense fluids. The HCB model has been applied to gas phase reaction dynamics and it successfully interprets steric effects on cross sections in oriented molecule reactions. Plans include extension of this model to incorporate energy bottlenecks in chemical reactions. When the HCB model is applied to the analysis of structural order in liquids, it predicts how the solvent aligns around a solute. The work will be extended to analyze long and short range orientational order in liquids of nonspherical molecules. The present analytical theory, combined with the computer simulations on precisely the same systems, provides an unobscured look at the properties of fluids of polyatomic molecules.