ACCURATE MODELING OF INTERMOLECULAR FORCES - A SYSTEMATIC MOLLER-PLESSET STUDY OF THE ARGON DIMER USING CORRELATION CONSISTENT BASIS-SETS

The argon dimer potential energy curve has been investigated using Moller-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.