Photochemical and Collisional Effects in Trace Atmospheric Species Monitoring

痕量大气物种监测中的光化学和碰撞效应

• 批准号: 9212767
• 负责人: David Crosley
• 金额: $ 30.05万
• 依托单位: SRI International
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-15 至 1996-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9212767&HistoricalAwards=false
• 关键词: Photochemical; Collisional; Effects; Trace; Atmospheric

In this project laboratory experiments on the OH radical pertinent to three major needs for monitoring particular trace species in the atmosphere will be carried out. The study of polarization of laser-induced fluorescence in the A-X electronic system of OH, and the modeling of state-to-state rotational energy transfer in the A-state, concern detection of OH itself in the troposphere. Transition probabilities for weak vibrational bands of the A-X system impact OH detection as well as studies of OH kinetics for atmospheric purposes. Collisional quenching of high rotational levels in the A-State, and the temperature dependence of this process, govern quantum yields in the measurement of stratospheric H2O with a Lyman-a hygrometer. HNO3 is a molecule difficult to detect at the low levels present in the relatively clean troposphere. SRI scientists study the nascent distribution of OH over vibrational and rotational levels, following the photodissociation of HNO3, and the relaxation of this distribution to a thermal one. These data are necessary for the design of a photoframentation/laser-induced fluorescence method for nitric acid monitoring.

在该项目中，将针对与监测大气中特定痕量物质的三个主要需求相关的 OH 自由基进行实验室实验。 OH 的 A-X 电子系统中激光诱导荧光的偏振研究，以及 A 态中状态到状态旋转能量转移的建模，涉及对流层中 OH 本身的检测。 A-X 系统弱振动带的跃迁概率影响 OH 检测以及大气 OH 动力学研究。 A 态高旋转能级的碰撞猝灭以及该过程的温度依赖性控制着莱曼湿度计测量平流层 H2O 时的量子产率。 HNO3 是一种难以在相对清洁的对流层中以低浓度检测到的分子。 SRI 科学家研究了 HNO3 光解后 OH 在振动和旋转水平上的新生分布，以及该分布松弛为热分布。 这些数据对于设计用于硝酸监测的光裂解/激光诱导荧光方法是必要的。