Interaction energy of water dimers from pressure broadening of near-IR absorption lines

Pressure broadening coefficients have been determined for three spectroscopic transitions of water vapour at wavelengths near 1.393 μm in the presence of noble gases. The interaction energy of the water dimer at room temperature was estimated from these pressure broadening coefficients using the Parmenter–Seaver relation. For the transitions investigated, the estimated interaction energies for the water dimer are: 20.4 ± 3.7, 12.3 ± 3.8 and 13.7 ± 3.3 kJ mol−1. The variation of the interaction energies reflects the rotational level dependence of the pressure broadening of these lines by the noble gases. The average of these values is compared to other experimental determinations.