  We investigate the basis-set convergence of electronic correlation energies
calculated using coupled cluster theory and a recently proposed finite
basis-set correction technique. The correction is applied to atomic and
molecular systems and is based on a diagrammatically decomposed coupled cluster
singles and doubles correlation energy. Only the second-order energy and the
particle-particle ladder term are corrected for their basis-set incompleteness
error. We present absolute correlation energies and results for a large
benchmark set. Our findings indicate that basis set reductions by two cardinal
numbers are possible for atomization energies, ionization potentials and
electron affinities without compromising accuracy when compared to conventional
CCSD calculations. In the case of reaction energies we find that reductions by
one cardinal number are possible compared to conventional CCSD calculations.
The employed technique can readily be applied to other many-electron theories
without the need for three- or four-electron integrals.
