Can incremental expansions cope with high-order coupled-cluster contributions?

Abstract

Local-correlation incremental expansions have been used for the evaluation of high-order coupled-cluster corrections to atomization energies, in exploratory calculations for small molecules. Expansion up to (at least) three-body terms seems to be necessary in terms of localized orbitals, within the occupied space, whereas truncation after two-body inter-atomic terms appears to be sufficient in the virtual space.

Keywords:

• ab initio
• coupled cluster
• increments