Accurate modeling of intermolecular forces: a systematic Møller-Plesset study of the argon dimer using correlation consistent basis sets

The argon dimer potential energy curve has been investigated using Møller-Plesset perturbation theory through fourth-order (MP4) and the recently developed augmented correlation consistent basis sets for argon. The interaction energy has been determined using the supermolecule approach; trends in both uncorrected and counterpoise-corrected values are examined. The best corrected values attained for the well depth and equilibrium separation are, respectively, 0.42 mE_h and 7.17 a₀, which are in very good agreement with the empirical values of 0.45 mE_h and 7.10 a₀. Moreover, the regularity of the trends for the four basis sets used allows estimates of the complete basis set MP4 values, 0.45 mE_h and 7.13 a₀.