Atmospherically Relevant Electronic States of O2 and Their Isotopes

9612366 斯兰格 分子氧的激发态在整个大气中普遍存在，它们的光谱学、辐射特性和动力学是确定大气区域的光物理学和光化学的基本要素。在这个项目中，将研究三个领域：a）动力学和反应性的O2（B）状态的振动激发水平，B）弱绑定，但潜在的重要状态的O2附近的解离极限，和c）探索同位素效应的O2光吸收在242 - 250 nm赫兹伯格带吸收区。 O2（B）态的研究主要是在其最低的振动能级，但有迹象表明平流层源涉及更高的振动能级，其动力学性质可能是重要的。O2的弱束缚态已经在各种背景下讨论过，但没有相关的测量。光腔衰荡光谱技术使得研究这些状态成为可能，这些状态在实验室和大气现象中都被认为是前体。臭氧、二氧化碳和一氧化二氮中大气氧同位素比值的变化是当前的研究热点，而光腔衰荡研究可能有助于解释这些效应。 ***

9612366 Slanger Excited states of molecular oxygen are ubiquitous throughout the atmosphere, and their spectroscopy, radiative properties, and kinetics are essential elements in determining the photophysics and photochemistry of atmospheric regions. In this project, three areas will be investigated: a) kinetics and reactivity of the O2(b) state in vibrationally excited levels, b) weakly bound but potentially important states of O2 lying near the dissociation limit, and c) exploration of isotope effects in O2 photoabsorption in the 242-250 nm Herzberg band absorption region. The O2(b) state has been studied primarily in its lowest vibrational level, yet there are indications of stratospheric sources involving much higher vibrational levels, and their kinetic properties could be important. The weakly-bound states of O2 have been discussed in various contexts, yet there are no relevant measurements. The technique of cavity ring-down spectroscopy is making it possible to investigate these states, which are implicated as precursors in both laboratory and atmospheric phenomena. Variability in atmospheric oxygen isotope ratios in ozone, carbon dioxide, and nitrous oxide are of current interest, and cavity ring-down studies may be helpful in explaining these effects. ***