The structure relaxation in nanocrystalline NiO (nano-NiO, 13 nm crystallite size) has been
studied by X-ray absorption spectroscopy at the Ni K-edge at 300 K. Conventional single-
scattering analysis of the EXAFS signals from the first two coordination shells showed a
lattice volume expansion by about 1% and a contraction of the Ni–O bonds by about 0.5% in
nano-NiO compared to microcrystalline NiO. A more sophisticated approach, based on a
combination of classical molecular dynamics and ab initio multiple-scattering EXAFS theory …