New intermolecular benchmark calculations on the water dimer: SAPT and supermolecular post‐Hartree–Fock approaches

Abstract

AbstractIn this contribution, we propose accurate intermolecular benchmarks for the 10 standardized water dimers initially proposed by van Duijneveldt et al., following a study by Smith et al. (J Chem Phys, 1990, 92, 1240). Using the popular triple‐zeta aug‐cc‐pVTZ basis set, symmetry‐adapted perturbation theory (SAPT) computations have been performed and compared with supermolecular post‐Hartree–Fock techniques up to most recent explicitly correlated methods. Effects of approximated inclusion of third‐order corrections to induction and exchange‐induction energies are discussed. As SAPT results are close to the best available ab initio ones, detailed analysis of the available individual SAPT contributions to the interaction energy confirms that electron correlation acts not only on its long‐range dispersion part but also on its separated physical components. This permits to assess the validity of the usual HF+Dispersion model as approximation to add pure correlation effects to orbital‐based interaction schemes. The study proposes extensive benchmark data in a Supporting Information part to provide useful data for the development and the test of new force field energy functions for water. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009