Kinetics of Atmospherically Important Radical-Molecule Complexes

对大气具有重要意义的自由基分子复合物的动力学

• 批准号: 0924146
• 负责人: Jaron Hansen
• 金额: $ 26万
• 依托单位: Brigham Young University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0924146&HistoricalAwards=false
• 关键词: Kinetics; Atmospherically; Important; Radical; Molecule

Recent experimental and computational studies have highlighted the effects of water vapor on the kinetics and product branching ratios of important atmospheric processes. In many cases, these reactions involve the OH and HO2 radical. To date, the literature only contains studies on the effects of water vapor for reactions involving the OH and HO2 radical. The formation of a radical-molecule complex during the reaction mechanism has been implicated as the reason for the perturbed kinetics and product branching ratios. This project presents experiments designed to measure the effects of water vapor on the kinetics of the 2-hydroxyethylperoxy radical (HOCH2CH2O2) self-reaction and reaction with hydroperoxy radical (HO2) using the method of laser flash photolysis/UV absorption spectroscopy/two-tone frequency modulated diode laser spectroscopy/laser induced fluorescence. Additional experiments to measure the effect of water vapor on the product branching ratio for the reaction of HOCH2CH2O2 + NO are also planned. The results of this work will provide fundamental insight into the reaction mechanism of atmospherically important processes and the role of radical-molecule complexes in perturbing the reactivity of organic peroxy radicals. An understanding of the effects of water vapor on the kinetics of these prominent organic species will serve to refine tropospheric models and improve their predictive capabilities. The results of this investigation would provide data so that generalizations about the influence of water vapor on a variety of reactions could be developed. This project will provide research and training opportunities for both graduate and undergraduate students at the PI's university as well as create research opportunities for undergraduates, mentored by the PI and faculty members from Brigham Young University's sister school, Brigham Young University-Idaho (BYUI). (BYUI has recently been accredited as a four year bachelor degree granting institution and currently does not have research facilities.) This program will provide resources so that a number of qualified and properly prepared undergraduates from BYUI can spend time in the PI's laboratory during summer months collecting kinetic data on important atmospheric reactions. Additionally, two series of video podcasts will be produced. One series will present the motivation behind the current research and describe the methods/instrumentation used as well as the conclusions reached after analysis of the data and will be used at BYU to teach an upper division/graduate level class in atmospheric chemistry and in another physical chemistry course. A second series of video podcasts will be made that are designed to supplement the material presented in the interdisciplinary classes as well as in a science fundamental class at BYUI as part of their General Education curriculum. These video podcasts will include information on the effects of the emission of organic molecules and their relationship to the production of tropospheric ozone and an introduction to kinetics and the usefulness of understanding the rate of reactions. The research described in this project will serve as the backbone for the discussion in these video podcasts. Podcasts will also be produced that relate the influence of pollution to climate change and how the research is related to this topic. They will be produced in a way that illustrates to the general public how much we know about atmospheric chemistry, but they will also highlight the questions/research that still needs to be done.

最近的实验和计算研究突出了水蒸气对重要大气过程的动力学和产品分支比率的影响。 在许多情况下，这些反应涉及OH和HO2自由基。 迄今为止，文献仅包含有关水蒸气对涉及OH和HO2自由基的反应的影响的研究。 反应机理中自由分子复合物的形成已被认为是扰动动力学和产物分支比率的原因。 This project presents experiments designed to measure the effects of water vapor on the kinetics of the 2-hydroxyethylperoxy radical (HOCH2CH2O2) self-reaction and reaction with hydroperoxy radical (HO2) using the method of laser flash photolysis/UV absorption spectroscopy/two-tone frequency modulated diode laser spectroscopy/laser induced fluorescence. 还计划了其他实验，以测量水蒸气对HOCH2CH2O2 + NO反应产品分支比的影响。 这项工作的结果将提供对大气重要过程的反应机理的基本见解，以及自由基分子复合物在扰动有机过氧自由基反应性中的作用。 了解水蒸气对这些突出有机物种动力学的影响将有助于改善对流层模型并提高其预测能力。 这项研究的结果将提供数据，以便可以开发出有关水蒸气对各种反应的影响的概括。该项目将为PI大学的研究生和本科生提供研究和培训的机会，并为PI和Brigham Young University的Brigham Young University-Insivers-Idaho（BYUI）的PI和教职员工为本科生创造研究机会。 （最近，BYUI被认可为四年学士学位授予机构，目前没有研究设施。）该计划将提供资源，以便在夏季，BYUI的许多合格且适当准备的本科生可以在PI的实验室中度过一段时间，以收集有关重要大气反应的动力学数据。此外，还将制作两个系列视频播客。 一个系列将介绍当前研究背后的动机，并描述对数据进行分析后所使用的方法/仪器的动机，并将在BYU使用大气化学和另一个物理化学课程中的上层/研究生级课程。 将制作第二项视频播客，旨在补充跨学科课程中介绍的材料以及在BYUI的科学基本课程中，作为其通识教育课程的一部分。 这些视频播客将包括有关有机分子排放的影响的信息及其与对流层臭氧的生产以及动力学介绍以及理解反应速率的实用性。 该项目中描述的研究将作为这些视频播客中讨论的骨干。 还将生产播客，将污染与气候变化的影响以及研究与该主题相关。 它们将以一种向公众说明我们对大气化学的了解的方式来生产它们，但它们还将突出仍需要做的问题/研究。