Laboratory Studies of the Kinetics and Photochemistry of Hydrogen Oxides (HOx) Cycling in the Lower Atmosphere

这项工作的重点是在对流层中的OH和HO2（HOx）自由基的化学循环目前的不确定性领域。 该项目将基于激光的诊断技术与新颖的实验方法相结合，研究有助于产生，损失和循环的几个基本过程的动力学和光化学。 将尽可能在实际大气条件下对这些过程进行隔离和研究。 具体的研究领域是：1）甲醛和丙酮的动力学和光化学。 2)详细的羟基自由基（OH）与二氧化氮（NO2）在大气条件下的重组机制，包括使用的光致碎片激光诱导荧光（LIF）计划直接监测过氧亚硝酸（HOONO），连同传统的LIF检测OH。 3)臭氧光解产生的氧原子（O1D）的量子产率在290和411 nm之间。 4)OH与丙烯和异戊二烯反应的动力学和机理，包括这些反应的甲醛产率的测量。该研究的更广泛的科学影响包括对大气氧化能力的理解的进展，在气候和城市污染等领域具有重要意义。 此外，博士后，研究生和高中水平的学生将有机会通过对实验大气化学的研究来学习。

This work is focused on areas of current uncertainty in the chemical cycling of OH and HO2 (HOx) radicals in the troposphere. The project combines laser-based diagnostic techniques with novel experimental approaches to study the kinetics and photochemistry of several elementary processes that contribute to the production, loss, and cycling of Hydrogen oxides (HOx). These processes will be isolated and studied under realistic atmospheric conditions to the fullest extent possible. The specific areas of investigation are: 1) Kinetics and photochemistry of formaldehyde and acetone. 2) The detailed mechanism of the recombination of hydroxyl radical (OH) with nitrogen dioxide (NO2) under atmospheric conditions, including the use of a photofragment laser-induced fluorescence (LIF) scheme to directly monitor peroxynitrous acid (HOONO), together with conventional LIF detection of OH. 3) The quantum yield of oxygen atom (O1D) production from the photolysis of ozone between 290 and 411 nm. 4) Kinetics and mechanisms of the reaction of OH with propene and isoprene, including measurement of the formaldehyde yield for these reactions.The broader scientific impacts of the research include progress in understanding of the oxidizing capacity of the atmosphere, with important implications in areas such as climate and urban pollution. In addition, students at the postdoctoral, graduate, and high school level will have opportunities to learn through research about experimental atmospheric chemistry.