He-broadening and shift coefficients of water vapor lines in infrared spectral region

The water vapor line broadening and shift coefficients in the ν1+ν2, ν2+ν3, ν1+ν3, 2ν3, 2ν1, 2ν2+ν3, and ν1+2ν2 vibrational bands induced by helium pressure were measured using a Bruker IFS 125HR spectrometer. The vibrational bands 2ν3 and ν1+2ν2 were investigated for the first time. The interaction potential used in the calculations of broadening and shift coefficients was chosen as the sum of pair potentials, which were modeled by the Lennard-Jones (6-12) potentials. The vibrational and rotational contributions to this potential were obtained by use of the intermolecular potential parameters and intramolecular parameters of H2O molecule. The calculated values of the broadening and shift coefficients were compared with the experimental data. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Parameters of broadening of water molecule absorption lines by argon derived using different line profile models

The water vapor absorption spectrum was measured in the spectral region 6700–7650 cm–1 with argon as a buffer gas. The room-temperature spectrum was measured using a Bruker IFS 125-HR Fourier Transform Spectrometer with high signal-to-noise ratio, with a spectral resolution of 0.01 cm–1, at argon pressures from 0 to 0.9 atm. The H2O absorption spectral line parameters are derived by fitting two line shape profiles (Voigt and speed-dependent Voigt) to the experimental spectrum. It is shown that the use of speed-dependent Voigt profile provides the best agreement with experimental data

Modification of the experimental setup of the FTIR spectrometer and thirty-meter optical cell for measurements of weak selective and nonselective absorptions

The improvement of the experimental setup based on a Fourier spectrometer Bruker IFS-125 and a 30-meter multipass optical cell is described. The improvement includes the cell equipment with a system of automated adjustment of the number of beam passes without cell depressurization and ensures the cell work at high temperatures

Measurements and calculations of H2-broadening and shifting parameters of water vapour transitions in a wide spectral region

The water vapour line broadening (γ) and shifting (δ) coefficients for 149 lines of 10 vibrational bands 2ν1, 2ν3, ν1 + ν3, 2ν2 + ν3, ν1 + 2ν2, ν2 + 2ν3, 2ν1 + ν2, 3ν2 + ν3, ν1 + 3ν2 and 6ν2 induced by hydrogen pressure were measured with a Bruker IFS 125 HR spectrometer. The measurements were performed at room temperature with a spectral resolution of 0.01 cm–1 and in a wide pressure range of H2. The calculations of the broadening coefficients γ and δ were performed in the framework of the semi-classical method using an effective vibrationally dependent interaction potential. The optimal sets of potential parameters that give the best agreement with the measured broadening coefficients for each vibrational band separately were found. Then combined experimental data of 16 vibrational bands of H2O perturbed by H2 were used to determine the analytical dependence of some potential parameters on vibrational quantum numbers. The analytical expressions that reproduce the broadening coefficients γ for different vibrational bands are proposed

Helium broadening parameters of water vapor in the 10,200 - 11,200 cm-1 spectral region

The He-broadening (γ) and shift (δ) coefficients of 76 rovibrational transitions belonging to the 3ν1, 3ν3, ν1 + 2ν2 + ν3, and 2ν1 + ν3 vibrational bands of H2O molecule were measured in the spectral range between 10,200 and 11,200 cm−1 with the spectral resolution of 0.01 cm−1 using a Bruker IFS 125HR FTIR spectrometer. The calculations of γ and δ were performed in the framework of the semi-classical method. It was shown that the vibrational dependence of the long-range as well as the short-range parts of an isotropic H2O-He interaction potential influence substantially the calculated broadening coefficients γ. The vibrationally and rotationally dependent analytical model for the broadening coefficients calculation is presented and discussed

Measurements and calculations of H2-broadening and shift parameters of water vapour transitions of the v1 + v2 + v3 band

The water vapour line broadening and shifting for 97 lines in the ν1 + ν2 + ν3 band induced by hydrogen pressure are measured with Bruker IFS 125 HR FTIR spectrometer. The measurements were performed at room temperature, at the spectral resolution of 0.01 cm−1 and in a wide pressure range of H2. The calculations of the broadening γ and shift δ coefficients were performed in the semi-classical method framework with use of an effective vibrationally depended interaction potential. Two potential parameters were optimised to improve the quality of calculations. Good agreements with measured broadening coefficients were achieved. The comparison of calculated broadening coefficients γ with the previous measurements is discussed. The analytical expressions that reproduce these coefficients for rotational, ν2, ν1, and ν3 vibrational bands are presented

Effective potentials for H2O-He and H2O-Ar systems. Isotropic induction-dispersion potentials

The vibrational and rotational dependence of the effective isotropic interaction potential of H2O–He and H2O–Ar systems, taken in the form of Lennard-Jones 6–12 potential has been analyzed. The analysis is based on the experimental line broadening (γ) and line shift (δ) coefficients obtained for different vibrational bands of H2O molecule perturbed by He and Ar. The first and second derivatives of the function C(1)(q) for the long-range part of the induction-dispersion potential with respect to the dimensionless normal coordinates q were calculated using literature information for the dipole moment and mean polarizability functions μ(q) and α(q), respectively. These derivatives have been used in the calculations of the quantities which determine the vibrational and rotational dependence of the long-range part of the effective isotropic potential. The optimal set of the derivatives for the function C(1)(q) is proposed. The comparison with the experimental data has been performed

Helium broadening parameters of water vapor in the 10,200 - 11,200 cm-1 spectral region

The He-broadening (γ) and shift (δ) coefficients of 76 rovibrational transitions belonging to the 3ν1, 3ν3, ν1 + 2ν2 + ν3, and 2ν1 + ν3 vibrational bands of H2O molecule were measured in the spectral range between 10,200 and 11,200 cm−1 with the spectral resolution of 0.01 cm−1 using a Bruker IFS 125HR FTIR spectrometer. The calculations of γ and δ were performed in the framework of the semi-classical method. It was shown that the vibrational dependence of the long-range as well as the short-range parts of an isotropic H2O-He interaction potential influence substantially the calculated broadening coefficients γ. The vibrationally and rotationally dependent analytical model for the broadening coefficients calculation is presented and discussed

Measurements and calculations of H2-broadening and shift parameters of water vapour transitions of the v1 + v2 + v3 band

The water vapour line broadening and shifting for 97 lines in the ν1 + ν2 + ν3 band induced by hydrogen pressure are measured with Bruker IFS 125 HR FTIR spectrometer. The measurements were performed at room temperature, at the spectral resolution of 0.01 cm−1 and in a wide pressure range of H2. The calculations of the broadening γ and shift δ coefficients were performed in the semi-classical method framework with use of an effective vibrationally depended interaction potential. Two potential parameters were optimised to improve the quality of calculations. Good agreements with measured broadening coefficients were achieved. The comparison of calculated broadening coefficients γ with the previous measurements is discussed. The analytical expressions that reproduce these coefficients for rotational, ν2, ν1, and ν3 vibrational bands are presented