The ground-state R-e, omega(e), and D-e of Au-2 are calculated using non-relativistic and scalar relativistic pseudopotentials (PP), which are compared with all-electron non-relativistic and Douglas-Kroll-Hess results, respectively, at ab initio and density-functional levels of theory. The correlation effects of electrons defined as a core part in the 'small-core' PPs are found be very small in both of accuracy, as well as non-relativistic PPs, for the ground states of AuH, AuCl, and Au-2.