For the full-coverage simulations, the dimensions of the simulation box have been chosen to minimize the mismatch between the dimensions of the graphite and the adlayer. In the case of the hexagonal structure, see Fig. , a simulation box containing 64 molecules were created from a rectangular unit cell with dimensions a=14.203 Å and b=24.599 Å replicated 8×4 over a rectangular graphite surface of dimensions A=113.62 Å and B=98.394 Å (temperature of 300 K during 10 ns).