X-ray study of the sharpness of the smectic A layer structure

Abstract
The intensity ratio of the second order to the first order Bragg reflection resulting from smectic A layering is reported for two compounds. In one case this ratio is small (∼ 10−3), which is of the same order as commonly reported. The second compound shows an intensity ratio which is two orders of magnitude higher. In the latter case, the spatial distribution function of the molecular centres of gravity cannot be taken as sinusoidal.