Perturbation theoretical and variational supermolecule calculations are performed for some model systems, such as He...He, H2...H2, and water-water dimers. The symmetry adapted second order PT calculations used in this paper are free of basis set superposition error, but the PT results are sensitive to the basis set and may show wrong R→0 asymptotics. Supermolecule calculations can only be compared to the PT results at the long range, where the latter involve less approximation and are inherently free from BSSE.
ASJC Scopus subject areas
- Physics and Astronomy(all)