Active Control of Chemical Reactions

在这个由化学部理论和计算化学项目资助的奖项中，Rice将研究量子多体系统进化的主动控制理论，以便建立在致密液相中可以实现单分子反应主动控制的条件。这些研究的主要重点将是开发新的方法变体，这些方法使用有或没有绝热人口转移的状态的相干激励。本文主要研究了气相和固相反应的受激拉曼绝热通道（STIRAP）激光激励方案的发展。其他有前途的方法以及分子动力学主动控制以前实现的改进和扩展也将被研究。在化学的进化过程中，对化学反应中产物形成的选择性控制一直是人们所追求的。利用这种控制反应的方法，可以使人们大部分或全部生成特定的产物。通过控制温度、压力、溶剂性质等外部因素，在宏观上完成了控制。随着可调谐激光的出现，人们希望在微观水平上控制产物的选择性，并且可以选择性地破坏分子内的单个键。人们很快发现，被分子吸收的能量不容易局限在单个键上，而是倾向于在整个分子中重新分布。然而，最近，激光选择化学的概念有了重生，由赖斯和其他人发展的理论表明，能量可以通过仔细选择规定形状的复杂激光脉冲序列来定位。如果能将这一理论应用于实验，就有可能实现化学反应微观选择性控制的目标。

In this award funded by the Theoretical and Computational Chemistry Program of the Chemistry Division, Rice will study the theory for the active control of the evolution of quantum many-body systems in order to establish conditions under which active control of a unimolecular reaction can be achieved in a dense liquid phase. The principal focus in these investigations will be on developing new variants of methods that use coherent excitation of states with or without adiabatic transfer of population. A main focus in on the development of new stimulated Raman adiabatic passage (STIRAP) laser excitation schemes for both gas phase and solution phase reactions. Other promising methods as well as refinements and extensions of previous implementations of active control of molecular dynamics will also be studied.Selective control of product formation in a chemical reaction has been sought persistently throughout the evolution of chemistry. Using such control of a reaction would allow one to generate a particular product mostly or completely. Control has been accomplished at the macroscopic level by manipulating 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 will be possible to realize the goal of microscopic selective control of chemical reactions.