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.
