Calculation of near edge structure

Near edge fine structure has the potential to solve problems related to localised electronic states and bonding. Theory and calculation provide the link between electronic or structural properties and features observed in an electron loss spectrum. A hierarchy of approximations for the calculation of near edge structure features is introduced and the importance of using a self-consistent charge density and potential is emphasised. The use of various electronic structure calculation methods and their application to near edge structure calculation is reviewed. Finally, core hole effects are discussed and examples presented for cubic BN showing that the core hole mainly enhances intensity near threshold.