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.

该项目涉及测试，扩展和将高临界理论方法应用于大气化学反应。它由三个任务组成。任务1是使用理论预测含氮大气物种的反应速率常数和分支比率。胺，亚胺和酰胺是从饲养场和其他生物来源发出的。胺可能会促进未来的工业排放，因为它们是二氧化碳捕获碳的工业方法的关键组成部分（减少温室气体排放）。对于某些从未通过实验测量的反应，将预测速率常数，因为含氮的反应物不稳定。任务2是通过将预测速率常数与关键大气反应的实验数据进行比较，以进一步测试半古典过渡SATE理论（SCTST）的准确性。 SCTST已被证明可以预测与羟基自由基与分子氢反应的实验相吻合，而没有任何经验调节。它还可以预测甲烷与实验非常吻合的氯原子的初始率常数。两种反应的预测氢/氘动物同位素效应（KIE）与现有的实验数据一样准确。 SCTST将进一步表征，然后用于预测几种其他大气反应的速率常数和KIE。任务3是通过明确纳入角动量的保护来扩展单分子和重组反应的主方程处理。这将大大改善现有的主方程，这些方程使用各种未经测试的近似值来避免明确的处理。新的主方程将用于生成基准，可用于预测速率常数并分析实验数据。气相化学动力学的所有区域将受益于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力的非平衡化学系统的模型。这些包括燃烧，化学制造，行星氛围和星体化学。结果，参数化，源代码和所有模型将在科学会议上介绍，并在同行评审的文献中发表，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。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培训。