  We have implemented noniterative triples corrections to the energy from
coupled-cluster with single and double excitations (CCSD) within the 1-electron
exact two-component (1eX2C) relativistic framework. The effectiveness of both
the CCSD(T) and the completely renormalized (CR) CC(2,3) approaches are
demonstrated by performing all-electron computations of the potential energy
curves and spectroscopic constants of copper, silver, and gold dimers in their
ground electronic states. Spin-orbit coupling effects captured via the 1eX2C
framework are shown to be crucial for recovering the correct shape of the
potential energy curves, and the correlation effects due to triples in these
systems changes the dissociation energies by about 0.1--0.2 eV or about 4--7\%.
We also demonstrate that relativistic effects and basis set size and
contraction scheme are significantly more important in Au$_2$ than in Ag$_2$ or
Cu$_2$.
