DIFFUSE NEUTRON-SCATTERING FROM CUBIC LITHIUM-SULFATE AT 908-K

The diffuse neutron scattering intensity for Li2SO4 at 908 K has been calculated using a treatment which includes correlation between thermal displacements of the atoms and reorientation of the SO42- ions. The calculation of the diffuse neutron diffraction scattering for Li2SO4 powder is based on a structural model obtained from a recent analysis of single crystal neutron Bragg reflections for the high temperature cubic phase of Li2SO4. Relatively large correlations are required between the displacements of the atoms (lambda(s(S)s(O)) and lambda(s)n(O)s(n')(O) for n not-equal n') to obtain good agreement between calculated and observed diffuse intensities. It is shown that evidence for a ''paddle-wheel mechanism'' is difficult to obtain from an analysis of the diffuse neutron scattering intensities.