Ortho-Para-Dependent Pressure Effects Observed in the Near Infrared Band of Acetylene by Dual-Comb Spectroscopy

Kana Iwakuni, Sho Okubo, Koichi M.T. Yamada, Hajime Inaba, Atsushi Onae, Feng Lei Hong, Hiroyuki Sasada

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


We demonstrate that dual-comb spectroscopy, which allows one to record broadband spectra with high frequency accuracy in a relatively short time, provides a real advantage for the observation of pressure-broadening and pressure-shift effects. We illustrate this with the ν1+ν3 vibration band of C212H2. We observe transitions from P(26) to R(29), which extend over a 3.8 THz frequency range, at six pressures ranging up to 2654 Pa. Each observed absorption line profile is fitted to a Voigt function yielding pressure-broadening and pressure-shift coefficients for each rotation-vibration transition. The effectiveness of this technique is such that we are able to discern a clear dependence of the pressure-broadening coefficients on the nuclear spin state, i.e., on the ortho or para modification. This information, combined with the pressure-shift coefficients, can facilitate a detailed understanding of the mechanism of molecular collisions.

Original languageEnglish
Article number143902
JournalPhysical review letters
Issue number14
Publication statusPublished - 2016 Sept 29

ASJC Scopus subject areas

  • General Physics and Astronomy


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