Off-specular X-ray diffuse scattering from a free suspended smectic film has been performed using different scanning geometries. Rocking scans and diffuse scans out of the plane of incidence are analyzed using a general formalism to describe the resolution function. The diffuse intensity is calculated via the use of Gaussian distributions for the resolution function within the framework of the first Born approximation. For each of the scanning geometries, practical analytical expressions are given which account well for the experimental data.

Physica B

Sentenac, D., Fera, A., Opitz, R., Ostrovskii, B. I., Bunk, O., & de Jeu, W. H. (2000). X-ray scattering from freely suspended smectic films: resolution and other effects. Physica B, 283, 232–236.