Femtosecond Dynamics of Bimolecular Reactions

双分子反应的飞秒动力学

• 批准号: 9107804
• 负责人: J. McDonald
• 金额: $ 49万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-06-01 至 1995-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9107804&HistoricalAwards=false
• 关键词: Femtosecond; Dynamics; Bimolecular; Reactions

Professor McDonald is funded by a grant from the Experimental Physical Chemistry Program to study the dynamics of chemical reaction processes on a time scale of approximately 250 femtoseconds, using time resolved spectroscopy with laser pulses of that length. The goal is to study the reaction in the time scale of the bond-making process itself. A van der Waals cluster containing one reactant and a nonreactive molecule that can be made into the other reactant by photodissociation provides a convenient definition of a zero of time for a bimolecular reaction. The reactions to be studied involve the addition of radicals and atoms H, Cl, Br, or methyl to small double-bonded molecules such as ethylene. Products formed in the reaction in a cooled molecular beam will be detected by femtosecond pump-probe laser fluorescence or by multiphoton-ionization with time-of-flight mass spectroscopy detection. %%% Very fast laser pulses will be used in a stroboscopic technique to study the reaction between two reactants to form new molecules. Starting with the reactants loosely bound in a cluster, a flash of light begins the reaction. The observations will be carried out with light pulsing at the time scale of the reaction process itself to see the making of a new bond in progress.

McDonald 教授获得实验物理化学项目的资助，利用具有该长度激光脉冲的时间分辨光谱来研究大约 250 飞秒时间尺度上的化学反应过程的动力学。 目标是研究成键过程本身的时间尺度内的反应。包含一种反应物和一种非反应性分子的范德华簇，可以通过光解离变成另一种反应物，为双分子反应的零时间提供了方便的定义。 要研究的反应涉及自由基和原子 H、Cl、Br 或甲基向小双键分子（例如乙烯）的加成。 在冷却分子束中的反应中形成的产物将通过飞秒泵浦探针激光荧光或多光子电离与飞行时间质谱检测来检测。 %%% 非常快的激光脉冲将用于频闪技术来研究两种反应物之间形成新分子的反应。从反应物松散地结合成簇开始，闪光开始反应。 将在反应过程本身的时间尺度上用光脉冲进行观察，以观察新键的形成过程。