Effect of Pb-Pb correlation in diffuse scattering of powder PbF2

Diffuse X-ray and neutron scattering from powder PbF2 are measured at 15 and 294 K. The oscillatory profile of diffuse scattering is explained by including the correlation effects among thermal displacements of atoms. The contribution of correlated thermal vibration of Pb-Pb atoms located at far-off distance to the oscillatory profile of diffuse scattering intensities is first confirmed.