DIFFUSE SCATTERING ACCOUNT INACCURATE DIFFRACTION STUDIES: A PRACTICAL APPLICATION A. I.Stash^*, V. E. Zavodnik^*, V. G. Tsirelson^#, D. Feil^$, ^*Karpov Institute of Physical Chemistry, Moscow, Russia, ^#Mendeleev University of Chemical Technology, Moscow, Russia, ^$University of Twente, Enschede, the Netherlands

Diffuse scattering ( dynamic and static ) contribution in diffraction intensities influences both thermal atomic parameters and electron density maps. It depends on concentration of defects contributing to scattering near Bragg position of the peak in the reciprocal space and is increased when temperature of the experiment is close to phase transition point. The experimental method of the diffuse scattering account was suggested in [1].We are presenting in this report the application of this method for studying of a few organic and inorganic compounds at different temperatures and for samples of quartz with different defect structures. The anisotropy of thermal diffuse scattering was found in the hexahydroquinolone crystals at room temperature and its increasing when temperature approached to phase transition point at 248 K.

Support of this research by the Netherlands Organization for Scientific Research (NWO) is gratefully acknowledged.

[1] Zavodnik V. E., Stash A. I., Tsirel'son V. G. and Feil D. (1994) Extended Abstracts SAGAMORE XI Charge, Spin and Momentum Densities, Brest, France, August 7 - 12, p. 259.