Abstract
We introduce a model to calculate the equilibrium configuration of the interface between two monolayers of large, planar organic molecules bonded by van der Waals (vdW) forces. The model significantly simplifies analysis by replacing the conventional atom-atom vdW potential summation with a single ellipsoidal potential centered in the molecular plane. Our results indicate that recent observations of crystalline ‘‘quasiepitaxial’’ vacuum growth of incommensurate lattices of these planar molecular films result from the relative intralayer stiffness as compared to the small interlayer shear stress. The model can be used to predict molecular structures which are likely to form quasiepitaxial layers.