In this paper, we estimate the type of orientation of H2O molecules adsorbed on the surface of airgel nanopores based on experimental data on the broadening of the vibrational-rotational lines of the H2O molecule during its collisions with H2O molecules on the surface of the airgel in their chaotic and ordered orientation. It is shown that the experimental data are consistent with the model of orderly oriented H2O molecules on the surface of SiO2 nanopores.
The nature of the pure water vapor continuum absorption in the rotational absorption band is investigated. The earlier retrieved continuum spectra at 296 and 326 K in the spectral region of 70–700 cm–1 are considered1 . The contribution of the absorption by water dimers is estimated at the level of no more than 50%. Two modern continuum models–water dimers and intermediate line wings–are jointly adopted to the new continuum spectra. It is shown that the model used allows describing the observed continuum spectra mainly in the central part of the rotational absorption band.
This paper presents results of the study of the water vapour continuum absorption within 8800 and 10600 cm-1 absorption bands. The continuum spectra recorded at increased temperatures (398, 431, and 471 K) and pressures are discussed on the basis of water dimer model1 supplemented by a contribution of intermediate line wings according to the model2 . The values of semiempirical parameters that characterize contribution and effective spectral width of the intermediate line wings are derived from fitting to the experimental continuum absorption spectra. A preliminary analysis of the temperature and pressure dependences of the fitted parameter is performed. It is shown that a better agreement between the simulated and experimental continuum spectra can be reached both within centre and in close wings of the absorption bands when intermediate line wings are accounted according to the model2 .
In this paper we investigate the water vapour continuum absorption retrieved from experimental high-resolution Fourier-Transform-Spectroscopy spectra, obtained earlier from high-temperature and pressure pure water vapour measuremets. The retrieved spectra of the water vapour continuum, related to the least-studied today near-IR absorption bands at 8800 and 10600 cm-1, are described on the basis of the water dimer hypothesis of the continuum. It is shown that water dimers should cause, at least, half of the water vapour continuum absorption in the studied spectral region. The temperature dependence of the effective dimerization constant is derived.
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