Configuration Interaction in Ni Metal and Ni Alloys and High-Energy Spectroscopy

We discuss the electronic state of Ni atoms in Ni metal and of Ni impurity in Cu and Au metals from the viewpoint of 3d configuration interaction (CI) using the Anderson impurity model including atomic multiplets. On the basis of the discussion, we give an interpretation for the Ni 2p-core X-ray photoemission spectrum (2p XPS) in Ni metal and Ni impurity systems and 3d photoemission spectra in Ni metal. The interpretation is, furthermore, shown to be consistent with the previous one for the 2p --> 3d circularly polarized X-ray absorption in ferromagnetic Ni using the CI approach.