2p Photoionization of atomic Ni: a comparison with Ni metal and NiO photoionization.

The photoabsorption spectrum of the 2p-3d resonances and the 2p photoelectron spectrum of atomic Ni were investigated both experimentally and theoretically. The analysis of the spectra takes into account that at the evaporation temperature of the metal at about 1800 K the fine structure states 3d(8) 4s(2) 3F and 3d(9) 4s 3D of both configurations 3d(8) 4s(2) and 3d(9) 4s are populated. The population of these two configurations offers the unique possibility for a comparison with the corresponding spectra in the condensed phase (Ni metal and NiO) where current configuration interaction calculations use the mixture of the configurations (3d,4s)(10). By using our theoretical description of the 2p photoionization new insight into these condensed phase spectra is found.