Environmental Science: Atmospheres is pleased to highlight the content that makes up our themed collection on ab initio reaction mechanisms. The full collection can be read here. In this blog, Associate Editor Stephen Klippenstein shares his thoughts on this topic and the articles published here:
The chemistry of the atmosphere is incredibly complex, with an enormous number of coupled reactions affecting key aspects of the atmosphere such as the concentration of aerosols. Various proposed responses to the global need for reducing our carbon emissions may dramatically alter emissions into the atmosphere. Quantitative models of the effect of such emissions are urgently needed. Such models rely on ever more detailed and accurate descriptions of a wide variety of elementary reactions. Ab initio studies of reaction mechanisms are a major contributor to the remarkable progress in our understanding of complex atmospheric reaction mechanisms.
This mini collection of articles provides three topical examples of the community efforts to advance our abilities to accurately model reaction mechanisms. The paper by Nguyen and Stanton on “Ab initio rate coefficients for the reaction of OH and H2O2 under troposphere and lower stratosphere conditions” demonstrates the utility of benchmark ab initio kinetics in mapping the rate constants for a simple but important reaction across wide ranges of temperature and pressure. There is an urgent to understand the global warming potentials of the molecules arising from the degradation of hydrofluoroolefins, which are a new class of refrigerants that are rapidly growing in importance. The paper by Watson and Beames on “Bimolecular sinks of Criegee intermediates derived from hydrofluoroolefins – a computational analysis” uses ab initio kinetics to map out a number of the key reaction rates and pathways for this new class of molecules. Highly oxygenated molecules, which are formed from the oxidation of various hydrocarbons, are important precursors to the formation of aerosols. The chemistry involved in the formation of such molecules is poorly understood. The reaction of two RO2 radicals provides one route to molecular growth that is expected to contributed to highly oxygenated molecule formation. The paper by Murphy et al. on “Accretion product formation in the self-reaction of ethene-derived hydroxy peroxy radicals” explores this chemistry in detail for a prototypical atmospheric hydrocarbon radical.
We hope you find these articles interesting. If you would like to contribute work on a similar topic, please feel free to send a proposal to esatmospheres-rsc@rsc.org, where a member of our editorial team will be happy to help.