Femtosecond studies of the influence of solvent on chemical reaction dynamics

溶剂对化学反应动力学影响的飞秒研究

• 批准号: 0617060
• 负责人: Stephen Bradforth
• 金额: $ 38.84万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0617060&HistoricalAwards=false
• 关键词: Femtosecond; studies; influence; solvent; chemical

In this award, funded by the Experimental Physical Chemistry program of the Chemistry Division, Professor Stephen Bradforth of the University of Southern California and graduate students will continue their investigation of liquid medium effects on photo-dissociation, explore new avenues in photo-initiated bimolecular reactions, and develop nonlinear optical spectroscopic techniques that can probe reactions at liquid surfaces. The photo-dissociation studies will focus on solvent effects on the dissociation of molecules such as ICN, BrCN and H2O2, and especially subsequent femtosecond time scale rotational relaxation of the diatomic fragments (CN and OH) produced in the dissociation. Comparison of experimental data with molecular dynamics simulations will aid in the evaluation of solvent effects on relaxation dynamics. The study of photo-initiated bimolecular reactions will involve photo-generation of OH radicals (from OH- or H2O2) and observation of their reaction with Cl- and Br- in the femtosecond regime. These radical-ion reactions are of emerging interest in atmospheric chemistry as possible routes to the formation of tropospheric Cl2 and Br2. Second order nonlinear optical techniques, which can provide surface-specific information, will be developed in order to explore reaction dynamics at liquid or aerosol particle surfaces. While the initial focus will be on solvation and mobility of photo-detached electrons, these techniques may eventually be applicable to the study of halogen formation reactions on sea-spray aerosols.In addition to the broad dissemination of research results through publications, conference and seminar presentations, Prof. Bradforth will also make available via his group website important innovations in instrumentation that may be useful to other groups working in ultrafast dynamics.

在化学系实验物理化学项目的资助下，南加州大学的斯蒂芬·布拉德福斯教授和研究生将继续研究液体介质对光解的影响，探索光引发的双分子反应的新途径，并开发能够探测液体表面反应的非线性光学光谱技术。光解离研究将集中在溶剂对ICN、BrCN和H_2O_2等分子解离的影响，特别是随后产生的双原子碎片(CN和OH)的飞秒时间尺度旋转弛豫。实验数据与分子动力学模拟的比较将有助于评价溶剂对驰豫动力学的影响。光引发双分子反应的研究将包括(从OH-或H_2O_2)光产生OH自由基，并在飞秒范围内观察它们与Cl-和Br2-的反应。这些自由基离子反应作为对流层Cl2和Br2形成的可能途径，在大气化学中引起了新的兴趣。为了探索液体或气溶胶颗粒表面的反应动力学，可以提供表面特定信息的二阶非线性光学技术将被开发出来。虽然最初的重点将是光分离电子的溶剂化和迁移率，但这些技术最终可能适用于海雾气溶胶上的卤素形成反应的研究。除了通过出版物、会议和研讨会演讲广泛传播研究成果外，布拉德福斯教授还将通过他的小组网站提供重要的仪器创新，这些创新可能对其他从事超快动力学研究的小组有用。