Laboratory Kinetics Studies of Peroxy Radical Reactions with Nitric Oxide

9622712 史蒂文斯 在这个项目中，异戊二烯基过氧自由基与一氧化氮的反应动力学的实验室调查将使用传统的，低压放电流技术，以及高压流技术在一个系统中进行，旨在隔离该反应的动力学。这些实验最终将利用各种方法来检测反应物和产物，特别是激光诱导荧光的羟基自由基，这将形成从感兴趣的过氧自由基。除了在环境条件下测量速率常数外，实验还将在广泛的压力和温度范围内进行，以充分表征反应的动力学。这些实验的结果将被纳入大气化学模型和基本化学反应性的理论研究，以测试和改善目前对大气氧化机制的理解。 这项研究的动机是最近的现场测量自由基浓度和它们的比例。已经观察到过氧化氢/羟基自由基浓度比的测量值之间的不一致性，特别是在低一氧化氮浓度的条件下。这表明，在我们理解的一氧化氮和过氧自由基之间的反应动力学的潜在问题，特别是那些来自较大的烃，如异戊二烯。这些反应的动力学的直接测量很少，特别是，没有涉及异戊二烯衍生的自由基。

9622712 Stevens In this project, laboratory investigations of the kinetics of the reaction of isoprene-based peroxy radicals with nitric oxide will be performed using both traditional, low-pressure discharge-flow techniques, as well as high-pressure flow techniques in a system designed to isolate the kinetics of this reaction. These experiments will eventually utilize a variety of methods for the detection of reactants and products, in particular, laser-induced fluorescence of hydroxyl radical, which will be formed from the peroxy radicals of interest. In addition to measuring the rate constant under ambient conditions, the experiments will be performed under a wide range of pressures and temperatures in order to fully characterize the kinetics of the reactions. The results of these experiments will be incorporated into atmospheric chemistry models and theoretical studies of fundamental chemical reactivity in order to test and improve the current understanding of atmospheric oxidation mechanisms. The study is motivated by recent field measurements of radical concentrations and their ratios. Discrepancies between measured values of the hydroperoxy/hydroxyl radical concentration ratio have been observed, particularly under conditions of low nitric oxide concentration. This suggests potential problems in our understanding of the kinetics of the reaction between nitric oxide and peroxy radicals, in particularly those derived from larger hydrocarbons, such as isoprene. There are few direct measurements of the kinetics of these reactions, in particular, none involving the isoprene-derived radicals.