Theoretical Studies of Reaction Dynamics

斯图尔特·赖斯教授得到了 理论和计算化学课程执行 化学动力学基本过程研究 目的（i）改进产品的激光控制理论 化学反应中的选择性，和（ii）提高 单分子反应速率理论 现有理论 用激光控制量子系统的演化， 扩展到非绝热反应的情况下，理论 将通过纳入反馈机制得到改善， 形成最佳激光场，而无需精确了解所有 系统哈密顿量中的分子参数。 的 单分子反应速率的现代描述 非线性力学将得到改进， 映射方法提供了一个精确的表示， 二自由度系统动力学 有很多自由度。结果将用于 研究了几种类型的单分子断裂， 异构化反应 一个量子版本的经典 单分子反应速率理论也将是 开发 %%% 产品形成的选择性控制的实现 在整个过程中一直在寻求反应， 化学的进化 到目前为止，这种控制只在 在宏观层面上，通过操纵 外部因素如温度、压力、溶剂 随着可调谐激光器的出现， 希望产品选择性可以控制在 微观层面上，在一个 分子可以被选择性地破坏。 很快 发现分子吸收的能量不容易 局限于单个债券，但更倾向于重新分配 整个分子。 然而，最近， 激光选择化学的概念已经重生，并且 赖斯和其他人提出的理论表明， 可以通过仔细选择一个复杂的序列 具有规定形状的激光脉冲 如果这个理论可以 实验性地付诸实践，仍然有可能 实现微观选择性控制的目的， 化学反应。

Professor Stuart Rice is supported by a grant from the Theoretical and Computational Chemistry Program to perform studies of elementary processes in chemical dynamics for the purpose of (i) improving the theory of laser control of product selectivity in a chemical reaction, and (ii) improving the theory of unimolecular reaction rates. Existing theories of laser control of the evolution of a quantum system will be extended to the case of nonadiabatic reactions, and the theory will be improved by incorporation of a feedback mechanism that shapes the optimal laser field without precise knowledge of all of the molecular parameters in the system Hamiltonian. The description of unimolecular reaction rates based on modern nonlinear mechanics will be improved by extension of the mapping methods which provide an exact representation of the dynamics of systems with two degrees of freedom to systems with many degrees of freedom. The results will be used to study several types of unimolecular fragmentation and isomerization reactions. A quantum version of the classical theory of unimolecular reaction rates will also be developed. %%% The achievement of selective control of product formation in a reaction has been sought persistently throughout the evolution of chemistry. To date, such control has only been accomplished at the macroscopic level, by the manipulation of external factors such as temperature, pressure, solvent character, etc. With the advent of the tunable laser, it was hoped that product selectivity could be controlled at the microscopic level, and that individual bonds within a molecule could be selectively broken. It was very quickly found that energy absorbed by a molecule was not easily localized in individual bonds, but preferred to redistribute throughout the molecule. More recently, however, the concept of laser selective chemistry has had a rebirth, and theories developed by Rice and others have shown that energy could be localized by carefully choosing a complex sequence of laser pulses of prescribed shapes. If this theory can be put to practice experimentally, it may still be possible to realize the goal of microscopic selective control of chemical reactions.