### Abstract

We report high-resolution ((Formula presented.) 0.001 cm^{−1}) Fourier Transform Infrared spectra of fluoroform (CHF_{3}) including the pure rotational (far infrared or THz) range (28–65 cm^{−1}), the ν_{3} fundamental ((Formula presented.) = 700.099 cm^{−1}), as well as the associated “hot’ band 2ν_{3} − ν_{3} ((Formula presented.) = 699.295 cm^{−1}) and the ‘atmospheric window’ range 1100–1250 cm^{−1} containing the strongly coupled polyad of the levels ν_{2}, ν_{5} and ν_{3} + ν_{6}, at room temperature and at 120 K using the collisional cooling cell coupled to our Bruker IFS 125 HR prototype (ZP2001) spectrometer and Bruker IFS 125 HR ETH-SLS prototype at the Swiss Light Source providing intense synchrotron radiation. The pure rotational spectra provide new information about the vibrational ground state of CHF_{3}, which is useful for further analysis of excited vibrational states. The ν_{3} fundamental band is re-investigated together with the corresponding ‘hot’ band 2ν_{3} − ν_{3} leading to an extension of the existing line lists up to 4430 transitions with J^{max} = 66 for ν_{3} and 1040 transitions with J^{max} = 43 for 2ν_{3} − ν_{3}. About 6000 transitions were assigned to rovibrational levels in the polyad ν_{2}/ν_{5}/ν_{3} + ν_{6} with J^{max} = 63 for ν_{2} ((Formula presented.) = 1141.457 cm^{−1}), J^{max} = 63 for ν_{5} ((Formula presented.) = 1157.335 cm^{−1}) and J^{max} = 59 for ν_{3} + ν_{6} ((Formula presented.) = 1208.771 cm^{−1})(K^{max} = J^{max} in each case). The resonance interactions between the ν_{2}, ν_{5} and ν_{3} + ν_{6} states have been taken into account providing an accurate set of effective hamiltonian parameters, which reproduce the experimental results with an accuracy close to the experimental uncertainties (with a root mean square deviation d_{rms} = 0.00025 cm^{−1}). The analysis is further extended to the ν_{4} fundamental ((Formula presented.) = 1377.847 cm^{−1}) interacting with 2ν_{3} ((Formula presented.) = 1399.394 cm^{−1}). The results are discussed in relation to the importance of understanding the spectra of CHF_{3} as a greenhouse gas and as part of our large effort to measure and understand the complete spectrum of CHF_{3} from the far-infrared to the near-infrared as a prototype for intramolecular quantum dynamics and rovibrational energy redistribution.

Original language | English |
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Pages (from-to) | 1091-1107 |

Number of pages | 17 |

Journal | Molecular Physics |

Volume | 116 |

Issue number | 9 |

DOIs | |

Publication status | Published - 3 May 2018 |

### Keywords

- CHF
- fluoroform
- FTIR
- greenhouse gas absorption
- high-resolution infrared spectroscopy
- intramolecular quantum dynamics
- THz

### ASJC Scopus subject areas

- Biophysics
- Molecular Biology
- Condensed Matter Physics
- Physical and Theoretical Chemistry

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## Cite this

^{12}CHF

_{3}and critical analysis of the infrared spectrum from 25 to 1500 cm

^{−1}.

*Molecular Physics*,

*116*(9), 1091-1107. https://doi.org/10.1080/00268976.2017.1392628