Minimum energy structures and interaction energies are obtained for a series of polycyclic aromatic hydrocarbons (PAHs) interacting with a methane molecule. The PAHs include benzene, naphthalene, anthracene, phenanthrene, tetracene, pyrene, and coronene. Interaction energies are calculated using complete-basis-set extrapolated MP2 plus a conventional or explicitly correlated CCSD(T) correction in moderately sized basis sets. As CCSD(T) calculations are not feasible for complexes larger than methane-coronene, a variety of novel dispersion-including DFT approaches are compared against the benchmark data. The top DFT performer is used to calculate interaction energies for larger complexes and to estimate methane adsorption energy on graphene and graphite. In addition, a variety of curved PAH structures are tested to illuminate the effect of nanotube curvature and chirality on the adsorption energy. The present study provides a benchmark for the design and tuning of approximate methods for an accurate description of hydrocarbon physisorption on carbon nanostructures.

Towards an accurate description of methane physisorption on carbon nanotubes

245th National Meeting (2013)

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