Noncovalent π−π Stacking and CH---π Interactions of Aromatics on the Surface of Single-Wall Carbon Nanotubes: An MP2 Study

Abstract

The magnitude and nature of interactions between small aromatic systems (benzene and naphthalene) and various single-wall carbon nanotubes are examined by MP2 theory. π−π stacking configurations are more strongly bound than CH---π analogues. There is a small preference for placement of the aromatic directly above a C═C bond center in the nanotube. All of these complexes are dominated by dispersion forces. Mobility of adsorbed benzene on the tube surface is considered in terms of rotating, tilting, and sliding. As noted previously for covalent modification of nanotubes, the computationally efficient same level different basis set protocol is reliable for studying noncovalent interactions. Previously reported DFT (LDA or GGA) binding energies for π−π stacking arrangements are underestimated, whereas dispersion-corrected methods overestimate these binding energies.