Extended diffuse regions in the X-ray diffraction pattern of anthracene single crystals: Part 1

Abstract

The extended diffuse regions appearing in the x-ray diffraction pattern of anthracene single crystals were recorded photographically in complete two-dimensional sections of the CuKα limiting sphere halfway between reciprocal lattice planes. The recorded density distributions were measured by a microdensitometer applying polarization, Lorentz and area distortion corrections and then transferred into undistorted reciprocal space. From the observed sections it was concluded that the extended diffuse regions form two hexagonally arranged interpenetrating `rod' systems in reciprocal space, each system of rods being perpendicular to one of two anthracene molecules in the unit cell. Under experimental conditions providing high resolution in reciprocal space some of the rod-shaped diffuse regions show internal structure with clearly recognizable drop of intensity in their central parts.