Nature Communications (Mar 2025)

Conformer-specific Infrared spectroscopy of cationic Criegee intermediates syn- and anti-CH3CHOO+

  • Ende Huang,
  • Licheng Zhong,
  • Jingning Xue,
  • Xiaohu Zhou,
  • Siyue Liu,
  • Li Che,
  • Hongwei Li,
  • Hongjun Fan,
  • Wenrui Dong,
  • Xueming Yang

DOI
https://doi.org/10.1038/s41467-025-57670-4
Journal volume & issue
Vol. 16, no. 1
pp. 1 – 9

Abstract

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Abstract Criegee intermediates are pivotal in atmospheric chemistry, yet their cationic forms remain poorly understood. This study presents the infrared spectra of cationic Criegee intermediates, specifically syn- and anti-CH3CHOO+, using vacuum ultraviolet photoionization coupled with IR photon dissociation spectroscopy. Combined with quantum chemistry calculations, we explore conformer-specific infrared spectra and identify distinct unimolecular reaction pathways for each conformer. Our method reveals structural differences between neutral and cationic CH3CHOO, including a lower isomerization barrier in the cationic form. This approach enables the investigation of conformer-specific IR spectroscopy for cationic species, which is challenging using direct IR absorption methods. By exploiting these distinct reaction pathways, we can conduct conformer-specific spectroscopic studies, advancing our ability to trace specific molecular conformations in complex chemical processes in both atmospheric and interstellar contexts.