Valence ionization energies of Ni(CN) 2–4, CO(CN) 3–6and Fe(CN) 4–6, studied by X-ray emission spectroscopy and ab initio molecular-orbital methods

Abstract

The valence ionization energies of Ni(CN)^2–₄, CO(CN)^3–₆and Fe(CN)^4–₆have been measured using X-ray emission spectroscopy. Ab initio molecular-orbital calculations of these ionization energies have been carried out at various levels of approximation and reveal the importance of both the different relaxation and correlation energies associated with metal and ligand localized ionizations.