Cohesive and surface energies ofπ-conjugated organic molecular crystals: A first-principles study

The intermolecular bonding properties of the oligoacene, oligophenylene, and oligothiophene series are addressed by density-functional theory, including nonlocal correlations, to account for the van der Waals interactions. The excellent agreement of our ab initio cohesive energies with available experimental data enables us to predict the surface energies, which are a prerequisite for understanding thin-film growth, and the resulting film morphologies of these complex anisotropic molecular crystals.