Origin of the anomalous X-ray diffraction in phthalocyanine films

The impact of the submolecular electron density on the X-ray diffraction profile of a layer-stacked thin film is studied experimentally and compared with numerical simulations based on the molecular structure and angular arrangement. Important structural information is contained in the X-ray diffraction profile of highly anisotropic molecular thin films, such as phthalocyanines. The results show that the intensity distribution of the diffraction peaks belonging to the same series of lattice planes provides important structural information including the molecular tilt angle and the center electron density of the molecule.