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The water vapour line-broadening (γ) and shift (δ) coefficients for 310 lines of 10 vibrational bands ν1, ν3, 2ν2, ν1+ ν2, ν2+ ν3,2ν2+ν3, 2ν1, ν1+ ν3, 2ν3and ν1+2ν2induced by argon pressure were measured with a Bruker IFS HR 125 spectrometer. The measurements were performed at room temperature, at the spectral resolution of 0.01 cm–1and over a wide pressure range of Ar. The calculations of the broadening coefficients γ and δ were performed in the framework of the semi-classical method. The intermolecular potential was taken as the sum of the atom–atom potential and the vibrationally and rotationally dependent isotropic induction+dispersion potential. The measured γ and δ were combined with literature data for the ν2and 3ν1+ν3, 2ν1+2ν2+ν3vibrational bands, and the optimal sets of potential parameters that gave the best agreement with the measured broadening coefficients for each vibrational band separately were found. Then, combined experimental data of 13 vibrational bands of H2O perturbed by Ar were used to determine the analytical dependence of some potential parameters on vibrational quantum numbers. [ABSTRACT FROM AUTHOR]

The line mixing effect for two pairs of transitions with rotational quantum numbers (3 1 2) ← (4 1 3), (3 2 1) ← (4 2 2), (4 3 1) ← (3 3 0) and (4 2 2) ← (3 2 1) in the ν1 + ν2 + ν3 band of H2O has been studied. The measurements were performed at room temperature, at the spectral resolution of 0.01 cm−1 and in a wide pressure range of helium. Pressure-broadening and -shifting coefficients and mixing parameter were obtained with help of the line profile using the Rosenkranz first-order approximation. [ABSTRACT FROM PUBLISHER]

The water vapor line broadening and shift in the ν 1 + ν 2 + ν 3 band induced by helium pressure were measured using a Bruker IFS 125HR FTIR spectrometer. The measurements were performed at room temperature at a spectral resolution of 0.01 cm−1 and in a wide He pressure range. The shifting coefficients δ are mainly positive, in contrast to the line center shift induced by other mono-atomic gases. Calculations of the coefficients γ and δ were performed in the framework of the semi-classical method. The influence of the rotational dependence of the isotropic intermolecular potential and accidental resonances in the H2O molecule on the shifting coefficients is discussed. Calculated values of line profile parameters are in a good agreement with observed parameters. [ABSTRACT FROM PUBLISHER]