Temperature-dependent determination of NO₂ dimerization reaction based on dual-comb spectroscopy

Dimerization reactions play a critical role in various fields of research, including cell biology, biomedicine, and chemistry. In particular, the dimerization reaction of 2NO₂⇌N₂O₄ has been extensively applied in pollution control and raw material preparation. Spectroscopy, as a powerful tool for investigating molecular structures and reaction kinetics, has been increasingly employed to study dimerization reactions in recent years. In this study, we successfully demonstrated the application of dual-comb spectroscopy (DCS) to analyze NO₂ dimerization reactions, making the first report on the application of this technique in this context. Parallel measurements of NO₂ and N₂O₄ fingerprints spectra with high resolution at 3000 cm^-1 was performed, benefiting from the unprecedented broadband and high-precision capability of DCS. The absorption cross-sections of N₂O₄ from 296 to 343 K was obtained from the measured spectra, which contributes to further research on the molecular spectrum of N₂O₄. These results demonstrate the potential of DCS for studying the dimerization reaction mechanism.