Accurate determination of line intensity of H2O near 7181 cm−1 : SI-traceable measurement using primary trace-moisture standard in N2 gas

• Published in: Journal of quantitative spectroscopy & radiative transfer 2023-12, Vol.311, Article 108784
• Main Authors: Hashiguchi, Koji, Amano, Minami, Cygan, Agata, Lisak, Daniel, Ciuryło, Roman, Abe, Hisashi
• Format: Article
• Language: English
• Subjects: CRDS; Multispectrum fitting; Spectral analysis; Trace moisture
• ISSN: 0022-4073; 1879-1352
• DOI: 10.1016/j.jqsrt.2023.108784

The absorption spectra of trace water vapor in N2 gas with a mole fraction of 500 nmol/mol in the pressure range of 20 kPa to 140 kPa were obtained near 7181 cm−1 using wavelength-meter-controlled cavity ring-down spectroscopy (WMC-CRDS). The reference gas (water vapor in N2 gas) was produced using a generation system of primary measurement standards for trace moisture in gases, where the amount of water vapor was measured using a gravimetric method. The obtained spectra of H2O were analyzed using a multispectrum fitting technique with a speed-dependent asymmetric Voigt profile (SDAVP). The values of the line intensity were determined with traceability to the International System of Units (SI). We could achieve the expanded uncertainty below 2 % for the line intensities of the strong lines. •The absorption spectra of H2O were recorded near 7181 cm−1 using wavelength-meter-controlled CRDS.•As a reference, the primary measurement standard for trace moisture in N2 gas was used.•The line-shape parameters were determined by a multispectrum fitting technique with an SDAVP.•The value of line intensity was determined with SI traceability.