No abstract

Odd oxygen (O[ 3 P], O[ 1 D], and O 3 ) is a key component of the atmosphere's oxidizing capacity. As such, tracing its evolution over time may provide better constraints on greenhouse-gas lifetimes, stratosphere-troposphere coupling, biosphere-atmosphere interactions, and radiative forcing in the past. Moreover, elevated odd-oxygen concentrations in the upper troposphere and stratosphere mean that a globally integrated record of odd-oxygen chemistry would be a unique window on the high-altitude atmosphere of the past, not just in terms of chemistry but also climate (

Chemical physics plays a large role in determining the isotopic compositions of gases in Earth's atmosphere, which in turn provide fundamental insights into the sources, sinks, and transformations of atmospheric gases and particulates and their influence on climate. This review focuses on the kinetic and photolysis isotope effects relevant to understanding the isotope compositions of atmospheric ozone, carbon dioxide, methane, nitrous oxide, and other gases and their historical context. The discussion includes non-mass-dependent isotope compositions of oxygen-containing species and a brief overview of the recent growth of clumped isotope measurements at natural isotopic abundances, that is, of molecules containing more than one rare isotope. The intention is to introduce chemistry researchers to the field of using isotope compositions as tracers of atmospheric chemistry and climate both today and back in time through ice and rock records and to highlight the outstanding research questions to which experimental and theoretical physical chemists can contribute. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 74 is April 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.