Abstract
Molecular overlapping of perylene tetracarboxylic diimides (PTCD) in Langmuir–Blodgett (LB) films is discussed. With the use of Kuhn's extended dipole model and spectral data in the visible and infrared regions, the degree of molecular overlap in a series of PTCD derivatives was determined. The results are in general agreement with the overlap values reported in X-ray studies for crystal packing of similar molecules.