Using symmetry in the framework of the incremental scheme: Molecular applications

An automatized procedure for the usage of symmetry within incremental coupled cluster calculations of molecular systems is described. We present a theoretical framework for the generation of symmetry-adapted one-site domains starting from a set of symmetric localized orbitals as well as a method to classify all n-site domains by symmetry classes. Finally, it is shown that the usage of approximately symmetric localized orbitals still leads to quite accurate correlation energies with errors below 1 kcal/mol.