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强调了水蒸气对重要大气过程的动力学和产物分支比的影响。 在许多情况下，这些反应涉及OH和HO 2自由基。 到目前为止，文献中只包含水蒸气对涉及OH和HO 2自由基的反应的影响的研究。 在反应机理过程中形成的自由基分子复合物已被牵连的扰动动力学和产品的分支比的原因。 本项目采用激光闪光光解/紫外吸收光谱/双音调频二极管激光光谱/激光诱导荧光的方法，测量了水蒸气对2-羟乙基过氧自由基（HOCH 2CH 2 O2）自反应和与氢过氧自由基（HO 2）反应动力学的影响。 另外的实验，以测量的HOCH 2CH 2 O2 + NO反应的产物的分支比的水蒸气的效果也计划。 这项工作的结果将提供基本的洞察大气中重要的过程和自由基分子复合物的作用，在扰动有机过氧自由基的反应性的反应机制。 了解水蒸气对这些主要有机物种动力学的影响将有助于改进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，使水蒸气对各种反应的影响的概括可以发展。该项目将为PI大学的研究生和本科生提供研究和培训机会，并为本科生创造研究机会，由PI和杨百翰大学的姐妹学校杨百翰大学爱达荷州分校（BYUI）的教师指导。 (BYUI最近被认可为四年制学士学位授予机构，目前没有研究设施。 该计划将提供资源，使一些合格的和适当的准备从杨百翰大学的本科生可以花时间在PI的实验室在夏季收集重要的大气反应的动力学数据。此外，还将制作两个视频播客系列。 一个系列将介绍当前研究背后的动机，并描述所使用的方法/仪器以及分析数据后得出的结论，并将在杨百翰大学用于教授大气化学和另一门物理化学课程的上层/研究生课程。 将制作第二系列视频播客，旨在补充BYUI跨学科课程和科学基础课程中的材料，作为其通识教育课程的一部分。 这些视频播客将包括关于有机分子排放的影响及其与对流层臭氧生成的关系的信息，并介绍动力学和了解反应速率的有用性。 本项目中描述的研究将作为这些视频播客中讨论的骨干。 还将制作播客，介绍污染对气候变化的影响以及研究如何与这一主题相关。 它们将以一种向公众展示我们对大气化学了解多少的方式产生，但它们也将突出仍然需要做的问题/研究。