Intermolecular potentials and second virial coefficients of the water-neon and water-argon complexes

We construct potential-energy surfaces for the water-neon and water-argon complexes from scaled perturbation theory, and calibrate them using accurate supermolecule data. Our best estimates of the binding energies for these two systems are 66.9 and 142.7 cm(-1), respectively, where the latter value is in good agreement with the spectroscopically determined AW2 potential. We calculate second virial coefficients, B-12(T), and the related property phi(12)=B-12-T(dB(12)/dT), and compare our results with experimental data for water-argon. The perturbation theory and AW2 B-12(T) results are consistent, and demonstrate that current theoretical approaches yield more precise second virial coefficient data than any in the literature. Our phi(12) calculations are in good agreement with experimental results derived from enthalpy-of-mixing data, though our estimated uncertainties are significantly smaller. (C) 2002 American Institute of Physics.