Low-Energy Electron Collisions with Copper and Gold Atoms

We have extended the $B$-spline $R$-matrix (close-coupling) method~[1] to fully account for relativistic effects in a Dirac-Coulomb formulation~[2]. The computer code was applied to electron-impact excitation of the $\rm (3d^{10}4s)^2S_{1/2} \to (3d^{10}4p)^2P_{1/2,3/2}$ and $\rm (3d^{10}4s)^2S_{1/2} \to (3d^{9}4s^2)^2D_{5/2,3/2}$ transitions in Cu and the corresponding transitions $\rm (5d^{10}6s)^2S_{1/2} \to (5d^{10}6p)^2P_{1/2,3/2}$ and $\rm (5d^{10}6s)^2S_{1/2} \to (5d^{9}6s^2)^2D_{5/2,3/2}$ in Au. Our numerical implementation of the close-coupling method enables us to construct term-dependent, non-orthogonal sets of one-electron orbitals for the bound and continuum electrons. This is a critical aspect in the present problems, especially for the outermost d and s orbitals. Furthermore, core-polarization effects are accounted for {\it ab initio\/} rather than through a model potential. Our results will be compared with recent experimental data~[3] and predictions from other theoretical approaches~[4]. [1]~O.~Zatsarinny, Comp. Phys. Commun. {\bf 174}, 273 (2006). [2]~O.~Zatsarinny and K. Bartschat, Phys. Rev. A {\bf 77}, 062701 (2008). [3]~M.~Maslov, P.J.O. Teubner, and M.J.~Brunger, Phys. Rev. A {\bf 77}, in press (2008). [4]~D.V.~Fursa, I. Bray, and R.P. McEachran, private communication (2008).