Ultraviolet Absorption of Transition Metal Halides

Abstract

The fundamental absorption spectra of the chlorides and the bromides of manganese, iron, cobalt, and nickel have been measured over the range from 2 to 40 eV. Fine structures occurring below 10 eV very as the transition metal changes. Spectral profiles 10 eV are simple and alike among the halides of different transition metals. Peaks located at the absorption edge shift systematically toward high energy from nickel halides to manganese halides, and are ascribed to the charge transfer transition from the outermost p orbitals of halogen to the unoccupied 3d orbitals of the transition metal. Comparison with soft X-ray absorption spectra suggests that the transitions from the outermost p orbitals of halogen to the 4 s orbitals of the transition metals produce peaks around 8 eV. Some of the other structures in the spectra are discussed.