Empirical relations and the X-ray absorption edge-shifts

All the existing qualitative rules and the empirical relations in the light of the available data on the X-ray absorption edge-shifts have been tested. Although the qualitative rules are still valid, the empirical relations are found to be inadequate in interpreting the data on edge-shifts. New empirical relations based on the concept of the effective ionic charge are proposed and tested. The success of these new relations in the case of each of the 3d10, 4p6, 5s2, 6p6, 4d10and 4f14isoelectronic series of compounds is established. The present results suggest that the edge-shifts are mainly governed by ionic charge and these depend linearly on the product of effective ionic charge and the electronegativity of the anion.