Preprint 107 published
Preprint 107, "Assessing the PAHAP potential with application to the exfoliation energy of graphite"
In this work we assess a recently published anisotropic potential for polycyclic aromatic hydrocarbon (PAH) molecules (J. Chem. Theory Comput. 2010, 6, 683-695). Comparison to recent high-level SAPT(DFT) results for coronene (C24H12) demonstrate the transferability of the potential whilst highlighting some limitations with simple point charge descriptions of the electrostatic interaction. The potential is also shown to reproduce second virial coefficients of benzene (C6H6) with high accuracy and this is enhanced by using a distributed multipole model for the electrostatic interaction. The graphene dimer interaction energy and the exfoliation energy of graphite have been estimated by extrapolation of PAH interaction energies. The contribution of non-local fluctuations in the p electron density in graphite have also been estimated which increases the exfoliation energy by 3.0 meV/atom to 47.6 meV/atom which compares well to recent theoretical and experimental results.