4840
The Electronic Structures of Silicon, Aluminum, and Magnesium in Tetrahedral Coordination with Oxygen from SCF-Xa M O Calculations J. A. Tossell Contribution f r o m the Division of Geochemistry, Department of Chemistry. University of Maryland, College Park, Maryland 20742. Received November 7, I974
Abstract: The electronic structures of the oxyanions s i 0 d 4 - , A10d5-, and Mg0d6- are calculated using the SCF-Xa scattered wave cluster MO method. The S o d 4 - calculation yields results in good agreement with available X-ray photoelectron, X-ray emission, and optical data for quartz (Si02) and other silicates. A detailed analysis of the X-ray spectra of Si02 yields an empirical MO diagram with uncertainties in valence orbital energies of
