The electron correlation and relativistic effects on ionization potentials and electron affinities of Cu, Ag, and Au are investigated in the framework of the coupled cluster method and different 1-component approximations to the relativistic Dirac᎐Coulomb Hamiltonian. The first-order perturbation approach based on the massvelocity and Darwin terms is found to be sufficiently accurate for Cu and Ag while it fails for Au. The spin-averaged Douglas᎐Kroll no-pair method gives excellent results for the studied atomic properties. The ionization potentials obtained within this method and Ž . the coupled cluster scheme for the electron correlation effects are 7.733 7. 735 eV for Cu, Ž . Ž . Ž 7.461 7.575 eV for Ag, and 9.123 9.225 eV for Au experimental values given in . Ž . parentheses . The calculated experimental electron affinity results for Cu, Ag, and Au Ž . Ž . Ž . are 1.236 1.226 , 1.254 1.303 , and 2.229 2.309 eV, respectively.
There is a marked relativistic effect on both the ionization potential and electron affinity of Ag which sharply increases for Au while Cu exhibits only a little relativistic character. A similar pattern of relativistic effects is also observed for electric dipole polarizabilities of the coinage metal atoms and their ions. The coupled cluster dipole polarizabilities of the coinage metal atoms calculated in this article in the Douglas᎐Kroll no-pair formalism Ž . Cu: 46.