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Abstract The study of the H 2 O dipole moment μ and polarisability α vibrational dependence is based on the comparison of experimental and calculated line shifts induced by argon, nitrogen, and air pressure in different H 2 O vibrational bands. Obtained dependence α on the stretching vibrations is in good agreement with the existing ab initio calculations in the literature, but the dependence α on the bending vibration is quite different. To clarify the dependence of μ and α on the bending vibration, the shifts of selected H 2 O lines of the 4ν 2 , 5ν 2 , and 6ν 2 bands induced by argon, hydrogen and helium pressure are measured with the help of a Bruker IFS HR 125 spectrometer at room temperature with a spectral resolution of 0.01 cm−1. The comparison of experimental and calculated results with different values of μ and α line shifts is given. Graphical Abstract Unlabelled Image Highlights • A new vibrational dependence of the H 2 O dipole moment was obtained. • The dipole moment and polarizability of H 2 O molecule from the line shift calculations. • The problem of the ambiguity for the highly excited bending states. [ABSTRACT FROM AUTHOR]

An analysis of the measured He-, Ar- and Kr- broadening coefficients γ for 1575 water vapor transitions of 27 vibrational bands belonging to the 0.6–11,200 cm−1 spectral region is performed using an empirical function that contains adjustable parameters. A universal function is detected during the analysis. This function depends on the parameters that are common for all perturbers A = (He, Ar or Kr). A universal function multiplied by one additional parameter x 20 (A) determines the broadening coefficients γ(A) for each perturber A = (He, Ar or Kr).Two fitting procedures are used. The first considers the fit of measured γ(exp) for individual rotational branches while the other considers the global fit of all 1575 measured γ(exp). In the second procedure, ratios of γ(Kr)/γ(He) = 2.543 ± 0.040 and γ(Kr)/γ(Ar) = 1.252 ± 0.036 are found. The coefficients derived from the fitted parameters are compared statistically to measured coefficients. Unlabelled Image • An analysis of the He-, Ar- and Kr- broadening coefficients for 1575 H 2 O transitions of 27 bands is presented. • A universal function is detected. • This function depends on the parameters that are common for all perturbers. [ABSTRACT FROM AUTHOR]