Computer Simulation of Chemical Dynamics

威廉·哈斯在理论和计算化学计划的支持下，在化学动力学的计算机模拟领域进行研究。这项研究通过发展精确的理论模型来模拟分子内动力学、能量传递以及化学动力学和动力学。同时考虑了原子核的量子力学处理和经典处理。此外，模拟既基于经典势能面，也基于由电子的量子力学处理确定的势能面。后一种技术，称为直接动力学，正在以一种允许与其他现成的电子结构代码直接和系统地接口的方式开发。目前正在研究的问题包括质子化多肽离子的表面诱导解离、臭氧在不饱和碳氢化合物表面的反应以及接近过渡态的分子内和单分子动力学理论。理解和控制化学反应的能力几乎影响到日常生活的方方面面、经济和我们对生命本身的理解。化学反应发生在原料合成和原油精炼过程中。了解如何在最少干预的情况下进行此类反应直接限制了产品的最终成本以及合成过程中产生的不需要的废物和/或热量的数量。从臭氧与不饱和碳氢化合物表面相互作用的模拟中获得的理解将直接转移到对流层中发生的类似过程。在对流层，这样的过程会导致臭氧消耗，还会在化学上改变海洋有机气溶胶，从而直接影响云的形成和阳光向地球表面的传输。这里开发的计算方法依赖于精确的势能面，因此直接耦合到用于此类目的的相关量子力学方法。学生和博士后科学家在课堂上、通过网络和与研究人员直接参与的方式进行培训。

William Hase is supported by the Theoretical and Computational Chemistry Program to perform research in the area of computer simulation of chemical dynamics. The research proceeds by development of accurate theoretical models for simulations of intramolecular dynamics, energy transfer, and chemical dynamics and kinetics. Both quantum mechanical and classical treatments of the nuclei are considered. Further, simulations are based on both classical potential energy surfaces and those determined from quantum mechanical treatments of the electrons. The latter technique, referred to as direct dynamics, is being developed in a way that allows for direct and systematic interfacing with other off-the-shelf electronic structure codes. Problems currently being studied include surface induced dissociation of protonated peptide ions, reaction of ozone on unsaturated hydrocarbon surfaces and the theory of intramolecular and unimolecular dynamics for approaching transition states.The ability to understand and control chemical reactions impacts practically every aspect of daily life, the economy and our understanding of life itself. Chemical reactions occur during synthesis of materials and during refinement of crude oil. Understanding how to make such reactions proceed with minimal intervention directly limits the ultimate cost of the product and the amount of unwanted waste materials and/or heat that are generated during synthesis. Understanding gleaned from simulation of ozone interactions with unsaturated hydrocarbon surfaces will be directly transferable to analogous processes that occur in the troposphere. In the troposphere, such processes lead to ozone depletion and also chemically alter oceanic organic aerosols that directly affect the formation of clouds and the transfer of sunlight to the surface of the earth. The computational methods developed here rely on accurate potential energy surfaces and are therefore coupled directly to relevant quantum-mechanical methods for such purposes. Students and postdoctoral scientists are trained in the classroom, via the web, and by direct participation with researchers.