Theoretical Analysis of Atmospheric Reactions

大气反应的理论分析

• 批准号: 1231842
• 负责人: John Barker
• 金额: $ 75.12万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1231842&HistoricalAwards=false
• 关键词: Theoretical; Analysis; Atmospheric; Reactions

This project involves testing, extending, and applying high-accuracy theoretical methods to atmospheric chemical reactions. It consists of three tasks. Task 1 is to use theory to predict reaction rate constants and branching ratios for nitrogen-containing atmospheric species. Amines, imines, and amides are emitted from feedlots and other biogenic sources. Amines may contribute to future industrial emissions because they are key components of an industrial method for carbon dioxide capture (to reduce greenhouse gas emissions). Rate constants will be predicted for some reactions that have never been measured experimentally because the nitrogen-containing reactants are unstable. Task 2 is to further test the accuracy of Semi-Classical Transition Sate Theory (SCTST) by comparing predicted rate constants with experimental data for key atmospheric reactions. SCTST has already been shown to predict ab initio rate constants in excellent agreement with experiments for the reaction of hydroxyl radical with molecular hydrogen, without any empirical adjustments. It also predicts ab initio rate constants for chlorine atoms with methane in very good agreement with experiments. The predicted hydrogen/deuterium kinetic isotope effects (KIEs) for both reactions are as accurate as the existing experimental data. SCTST will be characterized further and then used to predict rate constant and KIEs for several additional atmospheric reactions. Task 3 is to extend the Master Equation treatment of unimolecular and recombination reactions by explicitly incorporating conservation of angular momentum. This will significantly improve on existing Master Equations, which use various untested approximations to avoid the explicit treatment. The new Master Equation will be used to generate benchmarks and can be used to predict rate constants and to analyze experimental data.All areas of gas phase chemical kinetics will benefit from the characterization of SCTST. The benchmark Master Equation calculations will enable other researchers to test models for non-equilibrium chemical systems where collisions and chemical reactions are competitive. These include combustion, chemical manufacturing, planetary atmospheres, and astrochemistry. The results, parameterizations, source codes, and all models will be presented at scientific meetings, published in the peer-reviewed literature, and made freely available on the internet. These materials will add to the cyberinfrastructure of atmospheric chemistry. Students and postdoctoral research associates will be trained in the development and use of computational chemical kinetics methods.

该项目涉及对大气化学反应进行测试、扩展和应用高精度理论方法。它由三个任务组成。任务 1 是利用理论来预测含氮大气物质的反应速率常数和支化比。胺、亚胺和酰胺是从饲养场和其他生物来源排放的。胺可能会导致未来的工业排放，因为它们是二氧化碳捕获（以减少温室气体排放）的工业方法的关键组成部分。由于含氮反应物不稳定，因此将预测一些从未通过实验测量的反应的速率常数。任务 2 是通过将预测的速率常数与关键大气反应的实验数据进行比较，进一步测试半经典过渡态理论 (SCTST) 的准确性。 SCTST 已被证明可以预测从头开始的速率常数，与羟基自由基与分子氢反应的实验非常一致，无需任何经验调整。它还预测了氯原子与甲烷的从头计算速率常数，与实验非常一致。两个反应的预测氢/氘动力学同位素效应（KIE）与现有实验数据一样准确。 SCTST 将被进一步表征，然后用于预测其他几个大气反应的速率常数和 KIE。任务 3 是通过明确纳入角动量守恒来扩展单分子和重组反应的主方程处理。这将显着改进现有的主方程，后者使用各种未经测试的近似值来避免显式处理。新的主方程将用于生成基准，并可用于预测速率常数和分析实验数据。气相化学动力学的所有领域都将受益于 SCTST 的表征。基准主方程计算将使其他研究人员能够测试碰撞和化学反应具有竞争性的非平衡化学系统的模型。这些包括燃烧、化学制造、行星大气和天体化学。结果、参数化、源代码和所有模型将在科学会议上展示，在同行评审文献中发表，并在互联网上免费提供。这些材料将增加大气化学的网络基础设施。学生和博士后研究员将接受计算化学动力学方法的开发和使用方面的培训。