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IR Band profiling of dichlorodifluoromethane in the greenhouse window: high-resolution FTIR spectroscopy of ν2 and ν8.

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Version 2 2020-05-19, 14:14
Version 1 2020-05-19, 14:12
journal contribution
posted on 2020-05-19, 14:14 authored by CJ Evans, A Sinik, C Medcraft, D McNaughton, D Appadoo, EG Robertson
The IR spectrum of dichlorodifluoromethane (i.e., R12 or Freon-12) is central to its role as a major greenhouse contributor. In this study, high-resolution (0.000 96 cm(-1)) Fourier transform infrared spectra have been measured for R12 samples either cooled to around 150 K or at ambient temperature using facilities on the infrared beamline of the Australian Synchrotron. Over 14,000 lines of C(35)Cl2F2 and C(35)Cl(37)ClF2 were assigned to the b-type ν2 band centered around 668 cm(-1). For the c-type ν8 band at 1161 cm(-1), over 10,000 lines were assigned to the two isotopologues. Rovibrational fits resulted in upper state constants for all these band systems. Localized avoided crossings in the ν8 system of C(35)Cl2F2, resulting from both a direct b-axis Coriolis interaction with ν3 + ν4 + ν7 and an indirect interaction with ν3 + ν4 + ν9, were treated. An improved set of ground state constants for C(35)Cl(37)ClF2 was obtained by a combined fit of IR ground state combination differences and previously published millimeter wave lines. Together these new sets of constants allow for accurate prediction of these bands and direct comparison with satellite data to enable accurate quantification.

Funding

This experiments described here were undertaken on the far-IR beamline at the Australian Synchrotron, Victoria, Australia. Quantum chemistry calculations were carried out using facilities at Australia’s National Computational Infrastructure National Facility (NCI-NF).

History

Citation

J Phys Chem A, 2014, 118 (13), pp. 2480-2487

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Chemistry

Version

  • VoR (Version of Record)

Published in

Journal of Physical Chemistry A

Volume

118

Issue

13

Pagination

2480-2487

Publisher

American Chemical Society

eissn

1520-5215

Available date

2014-03-10

Publisher version

https://pubs.acs.org/doi/10.1021/jp501302q

Language

eng

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