Quantifying the 'Subtle Interplay' between Intermolecular and Molecule-Substrate Interactions in Molecular Assembly on Surfaces

The effect of the concurrent action of intermolecular and molecule-substrate interactions on the two-dimensional (2-D) self-assembly of organic molecules on solid surfaces is investigated in a combined experimental and theoretical effort. Scanning tunnelling microscopy measurements of terephthalic acid on the Cu(111) surface, a model system where the interplay between the two interactions is particularly evident, are used to develop a general, simple and computationally inexpensive model that quantitatively accounts for the experimental observations. The model, related to the well-known Frenkel-Kontorova model, offers a comprehensive description of the 'subtle interplay' between intermolecular and molecule-substrate interactions and provides a qualitative and quantitative predictive capability in the design and fabrication of 2-D molecular nanostructures at surfaces