Infrared detection of Criegee intermediates

Abstract

In this mini‐review article, we present the recent progress of utilizing three types of infrared (IR) spectroscopic tools to investigate the chemistry of Criegee intermediates (CIs). The first part of this article described a recent work of Wang et al., which utilized rapid‐scan FTIR to detect CIs created from ozonolysis. The second part of this article describes the advantages of quantum cascade lasers (QCLs) used as novel IR spectroscopic tools to probe CIs and the key concepts of experimental implementations. We also summarize the works of Chang and co‐workers, which utilized distributed feedback QCLs with thermal chirping to detect the simplest CI, CH2OO, and the subsequent kinetics measurements, such as reactions of CH2OO with ozone, CH3SH, and dimethyl sulfoxide. In the last part of this article, we described the key ideas of external‐cavity QCLs coupled with off‐axis integrated cavity output spectroscopy, which was proposed by Chung et al., and also the latest progress on determination of the band strength of CH2OO and its rate coefficient with O3.

Water Plays Multifunctional Roles in the Intervening Formation of Secondary Organic Aerosols in Ozonolysis of Limonene: A Valence Photoelectron Spectroscopy and Density Functional Theory Study

“…Among various possible sources of aerosols, ozonolysis of monoterpenes (C 10 H 16 ) has been considered as one of the most important sources of secondary organic aerosols (SOAs), which is generally perceived to take place via the “Criegee mechanism”, involving multiple generations of reaction intermediates, including primary ozonides (POZs), Criegee intermediates (CIs), hydroperoxides (HPs) and secondary ozonides (SOZs), which eventually lead to the formation of SOAs . Even though a variety of spectroscopic approaches, including vibrational spectroscopy, − ultraviolet (UV) absorption spectroscopy, , and numerous mass spectrometry-based methods, − have been used to investigate ozonolysis of monoterpenes, to the best of our knowledge, the valence electronic properties of monoterpene aerosols and their ozonolysis SOAs have not been reported to date, though the valence electronic structures are crucial in governing their chemical reactivity, especially when aerosols are involved in the redox chemistry or when they age progressively via oxidation.…”