X-ray photoelectron spectra and molecular orbital interpretation of the valence region of ClO4- and SO42-

X-ray photoelectron spectra are presented of the valence regions (0-4 eV binding energy) of the iso-electronic anions ClO4- and SO42-. The photoelectron lines are assigned on the basis of existing molecular orbital calculations and available X-ray fluorescence data. The intensities of the photoelectron lines are qualitatively accounted for by considering molecular orbital coefficients, orbital degeneracies, and atomic orbital cross sections for ionization.