Vibrational dependence of an intermolecular potential for H2O-He system

- Broadening and shift coefficients of lines for 9 H2O bands, perturbed by He are measured.
- The parameters of the intermolecular potential for H2O-He system are obtained.
- Vibrational dependence of intermolecular potential for H2O-He system is shown.

The intermolecular interaction potential, taken as the sum of pair potentials which, in turn, were modeled by the Lennard-Jones potential has been determined by means of nonlinear least squares fitting its parameters to the experimental data on the lines broadening (γ) and shift (δ) coefficients. The data on γ and δ for nine vibration bands ν1, ν3, 2ν2, ν1+ν2, ν2+ν3, 2ν1, ν1+ν3, 2ν2+ν3 and ν1+ν2+ν3 have been obtained from the analysis of the H2O-He absorption spectra, recorded from 3000 to 9000 cm−1 with help of IFS 125HR Fourier spectrometer at room temperature, spectral resolution of 0.01 cm−1 and in wide pressure range of He. Additionally we use literature data for rotational band (∼180 GHz) and ν2 band (1850-2140 cm−1). The vibrational and rotational dependence of the potential parameters as well as the temperature dependence of the calculated lines broadening coefficients have been demonstrated.