Chapter 4 - Wavefunction Theory Approaches to Noncovalent Interactions

Abstract

Listen

Translate article

This chapter describes how even ab initio quantum chemistry methods can be challenged to provide accurate results for noncovalent interaction energies. Convergence of energies with respect to electron correlation treatment and basis set are discussed, with the finding that only the “gold standard” of quantum chemistry, coupled-cluster through perturbative triple excitations [CCSD(T)], is consistently reliable among the traditional hierarchy of quantum chemistry methods, and then only in the complete basis set (CBS) limit. Effective ways to estimate the CCSD(T)/CBS limit are discussed. Numerous proposals have been made for ways to improve the accuracy of more approximate wavefunction methods for noncovalent interaction energies. These are compared and assessed against a common set of benchmark-quality CCSD(T)/CBS interaction energies. Finally, the performance of some of the best wavefunction methods is also compared to that of density functional approximations and symmetry-adapted perturbation theory.