X-Ray Photoemission Spectra of the Valance Electrons in Transition Metal Halides

The energy spectra of valance electrons photoemitted by excitation with X-rays have been measured on the chlorides and the bromides of nickel, cobalt, iron, and manganese. The profiles of the spectra obtained by deconvoluting raw data with a measured instrumental response function show structures representing the energy dependence of the state-densities of 3d electrons of metal ions. The structures in the spectra are qualitatively in terms of the molecular orbital energy levels. Variations in the spectral among different materials are discussed in connection with the fundamental optical absorption spectra.