Spectroscopy and Reaction Dynamics of Activated Entrance Channel Complexes

激活的入口通道复合物的光谱学和反应动力学

• 批准号: 9729234
• 负责人: Marsha Lester
• 金额: $ 43.98万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-15 至 2001-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9729234&HistoricalAwards=false
• 关键词: Spectroscopy; Reaction; Dynamics; Activated; Entrance

Marsha Lester of the University of Pennsylvania is supported by the Experimental Physical Chemistry Program in her ongoing studies to characterize the intermolecular potential, inelastic scattering and reaction dynamics of vibrationally activated entrance channel complexes composed of a hydroxyl radical and a reactive molecular partner (carbon monoxide, nitric oxide, water). Infrared excitation will provide sufficient energy to overcome the activation barrier to reaction while intermolecular excitations will orient the reactants such that the structure of the complex approximates that of the transition state. Prof. Lester will use double resonance techniques to record the mid- and near-IR spectra of the OH stretch as well as intermolecular bending levels of the OH complexes. Spectral measurements should yield information on the potential energy surfaces in the entrance channel to reaction for ground state and vibrationally excited reactants. The hydroxyl radical plays a pivotal role in the chemistry of the lower atmosphere. It is known as the `atmosphere's detergent` because its reactions prevent the accumulation of most trace gases in the atmosphere, many of which would act as air pollutants and greenhouse gases. For the majority of hydrogen-containing molecules emitted into the troposphere, reaction with the OH radical is their major, if not sole, chemical loss process. Thus, reaction with OH radicals leads to the removal of these compounds from the atmosphere and limits their atmospheric concentrations. Much experimental work has already been performed to evaluate the OH radical kinetics and reaction mechanisms under the conditions encountered in the atmosphere. In these studies, Prof. Lester will use techniques developed in her laboratory to take a much closer look at the reactions dynamics of OH radicals with molecular partners of atmospheric relevance such as carbon monoxide, nitric oxide and water.

宾夕法尼亚大学的玛莎·莱斯特得到了 实验物理化学计划在她正在进行的研究， 表征分子间势、非弹性散射和 振动激活入口通道复合物的反应动力学 由羟基自由基和活性分子伴侣（碳）组成 一氧化物、一氧化氮、水）。 红外激发将提供 足够的能量来克服反应的活化势垒， 分子间激发将使反应物取向， 复合物的结构接近过渡态的结构。 莱斯特教授将使用双共振技术来记录中期和中期 OH伸缩以及分子间弯曲的近红外光谱 OH复合物的水平。 光谱测量应该能得到 入口通道中势能面的信息， 基态和振动激发反应物的反应。 羟基自由基在低级化学中起着关键作用， 气氛 它被称为“大气的清洁剂”，因为它 反应防止了大气中大多数痕量气体的积累， 其中许多会成为空气污染物和温室气体。 为 大多数含氢分子被排放到对流层， 与OH自由基的反应是它们的主要化学损失，如果不是唯一的话 过程 因此，与OH自由基的反应导致去除这些 大气中的化合物，并限制其大气 浓度的 已经进行了大量的实验工作， 评估OH自由基动力学和反应机理下， 在大气中遇到的情况。 在这些研究中，莱斯特教授 将使用她实验室开发的技术， 看看OH自由基与分子伴侣的反应动力学 大气相关性，如一氧化碳、一氧化氮和水。