Electronic absorption spectroscopy and photochemistry of Criegee intermediates

Tolga N V Karsili*, Barbara Marchetti, Marsha I Lester, Michael N R Ashfold

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

10 Citations (Scopus)
34 Downloads (Pure)


Interest in Criegee intermediates (CIs), often termed carbonyl oxides, and their role in tropospheric chemistry has grown massively since the demonstration of laboratory-based routes to their formation and characterization in the gas phase. This article reviews current knowledge regarding the electronic spectroscopy of atmospherically relevant CIs like CH2OO, CH3CHOO, (CH3)2COO and larger CIs like methyl vinyl ketone oxide and methacrolein oxide that are formed in the ozonolysis of isoprene, and of selected conjugated carbene-derived CIs of interest in the synthetic chemistry community. Of the aforementioned atmospherically relevant CIs, all except CH2OO and (CH3)2COO exist in different conformers which, under tropospheric conditions, can display strikingly different thermal loss rates via unimolecular and bimolecular processes. Calculated photolysis rates based on their absorption properties suggest that solar photolysis will rarely be a significant contributor to the total loss rate for any CI under tropospheric conditions. Nonetheless, there is ever-growing interest in the absorption cross sections and primary photochemistry of CIs following excitation to the strongly absorbing 1ππ* state, and how this varies with CI, with conformer and with excitation wavelength. The later part of this review surveys the photochemical data reported to date, including a range of studies that demonstrate prompt photo-induced fission of the terminal O–O bond, and speculates about possible alternate decay processes that could occur following non-adiabatic coupling to, and dissociation from, highly internally excited levels of the electronic ground state of a CI.

Original languageEnglish
Pages (from-to)4-18
Number of pages15
JournalPhotochemistry and Photobiology
Issue number1
Early online date17 Jun 2022
Publication statusPublished - 20 Jan 2023

Bibliographical note

Funding Information:
The work was supported by the National Science Foundation under grant no. 2003422 (TNVK). Partial support was provided by the U.S. Department of Energy Basic Energy Sciences under grant DE‐FG02‐87ER13792 (MIL).

Publisher Copyright:
© 2022 American Society for Photobiology.


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