Electron-energy-loss spectra of NiO

The electron-energy-loss spectra of NiO have been calculated by the ab initio full-potential linearized augmented plane-wave method within the $\mathrm{L}\mathrm{D}\mathrm{A}+U$ approximation and compared with experimental spectra obtained in transmission electron microscopy. The results of standard calculation schemes generally agree with the experimental O K edge of NiO, though the calculated spectrum looks a little contracted along the energy axis in comparison with the experimental one. However, reducing the magnetic moment at Ni atoms by a temperaturelike parameter allows us to obtain a solution which fits very closely to experiment. Possible reasons for the disagreement of standard calculation with experiment are discussed.