The origin and intensities of low energy satellite lines in X-ray emission spectra: a molecular orbital interpretation

The occurrence of low energy satellite peaks in X-ray emission spectroscopy is briefly reviewed and the theories to explain their origin are discussed. A molecular orbital model is presented and the application of this method to the X-ray fluorescence transitions observed in silica, based on the SiO 4 unit, is described in detail. The arguments are extended to the compounds of other second row main group elements. It is found that the molecular orbital approach describes the observed trends in satellite main peak energy separation more accurately than the crossover transition theory of O'Brian and Skinner (1970). It is suggested that low energy satellite peaks arise from the perturbation and splitting of atomic orbitals due to bond formation.