Measurement and temperature dependence of the water vapor self-continuum between 70 and 700 cm−1

• Published in: Journal of molecular structure 2020-06, Vol.1210, p.128046, Article 128046
• Main Authors: Odintsova, Tatyana A., Tretyakov, Mikhail Yu, Simonova, Anna A., Ptashnik, Igor V., Pirali, Olivier, Campargue, Alain
• Format: Article
• Language: English
• Subjects: Bimolecular absorption; Continuum; FT-Spectroscopy; Optics; Physics; Rotational band; Temperature dependence; Water vapor
• ISSN: 0022-2860; 1872-8014; 0022-2860
• DOI: 10.1016/j.molstruc.2020.128046

We present new measurements and analysis of the water absorption spectra in the region of the rotational band, between 70 and 700 cm−1. The higher pressures of the recordings (up to 16 mbar) as compared to our previous measurements allowed us to extend the retrieval of the water vapor self-continuum absorption from 500 to 700 cm−1 and to test our earlier results up to 500 cm−1. As a result, the continuum amplitude at high wavenumbers, determined with smaller uncertainty, shows an improved agreement with literature experimental data. The measurements were performed at two temperatures (296 and 326 K) using two radiation sources of significantly different power ranges: SOLEIL synchrotron and globar. The quadratic pressure dependence of the self-continuum absorption was verified leading to consistent values of cross-sections derived at various experimental conditions. In addition, we obtained the first data concerning the water vapor self-continuum temperature dependence in the 84-365 cm−1 spectral range for which we present the preliminary analysis considering the available measurements and theoretical data. •H2O self-continuum absorption is retrieved in the 70-700 cm−1 range.•The T-dependence of the continuum is derived firstly between 84 and 365 cm−1.•Contributors to the continuum within the entire H2O rotational band are discussed.