Absolute frequency metrology of the CHF3 8.6-µm ro-vibrational spectrum at 10−11 level

• Published in: Journal of quantitative spectroscopy & radiative transfer 2020-06, Vol.248, p.106963, Article 106963
• Main Authors: Vicentini, Edoardo, Maddaloni, Pasquale, Aiello, Roberto, Gambetta, Alessio, Coluccelli, Nicola, Molteni, Lisa M., Castrillo, Antonio, Gianfrani, Livio, De Natale, Paolo, Laporta, Paolo, Galzerano, Gianluca
• Format: Article
• Language: English
• Subjects: CHF3 ro-vibrational spectrum; Optical-frequency-comb-assisted absolute frequency metrology; Wavelength-modulation Lamb-dip spectroscopy
• ISSN: 0022-4073; 1879-1352
• DOI: 10.1016/j.jqsrt.2020.106963

•The absolute line center frequencies of 59 lines were measured with a fractional uncertainty ranging from 9  ×  10−11 to 2 ×  10−11, which represents a two-order-of-magnitude improvement with respect to our previous studies [A].•In addition, a detailed comparison with recent high-resolution FTIR measurements [B] was also accomplished, bringing out an enhancement in the accuracy performance by more than three orders of magnitude. An optical-frequency-comb-referenced quantum cascade laser is used to perform wavelength-modulation Lamb-dip spectroscopy on a large number of ro-vibrational transitions falling in the CHF3υ5 fundamental band at 8.6 µm. The combined (statistical + systematic) fractional uncertainty in the absolute determination of the line-center frequencies ranges from 9×10−11 down to 2×10−11. This represents an improvement by more than two orders of magnitude, as compared to a recent and extensive study performed with a high-resolution FTIR spectrometer [1]. Our investigation realizes a sharpened knowledge of the CHF3 spectrum over a wide interval, also managing to accurately determine the positions of very close, previously unresolved multiple ro-vibrational components.