Vibrational dependence of an intermolecular potential for H₂O-He system

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 9000cm^-1 with help of IFS 125HR Fourier spectrometer at room temperature, spectral resolution of 0.01cm^-1 and in wide pressure range of He. Additionally we use literature data for rotational band (~180GHz) and ν₂ band (1850-2140cm^-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.