Band-Structure Contributions to X-Ray Emission and Absorption Spectra and Edges in Magnesium

The soft-x-ray $L_{2,3}$ emission and absorption spectra of Mg metal have been determined by means of high-resolution ab initio augmented-plane-wave calculations. The inclusion of transition-matrix elements calculated from the augmented-plane-wave wave functions changes the sharp structure found in the joint density of states, yields an $L_{2,3}$ emission spectrum in good agreement with experiment, and indicates that band-structure effects play an important role in the observed x-ray threshold shape.