Adsorption of Aromatic and Anti-Aromatic Systems on Graphene through π−π Stacking

• The adsorption of neutral (poly)-aromatic, antiaromatic, and more generally π-conjugated systems on graphene is studied as a prototypical case of π-π stacking. To account for dispersive interactions, we compare the recent van der Waals density functional (vdw-DF) with three semiempirical corrections to density functional theory and two empirical force fields. The adsorption energies of the molecules binding to graphene predicted by the vdw-DFwere found to be in excellent agreement with temperature desorption experiments reported in litera- ture,whereas the results of theremaining functionals andforce fields only preserve the correct trends. The comparison of the dispersive versus electrostatic contribu- tions to the total binding energies in the aromatic and antiaromatic systems suggests that π-π interactions can be regarded as being prevalently dispersive in nature at large separations, whereas close to the equilibrium bonding distance, it is a complex interplay between dispersive and electrostatic Coulombic interactions. Moreover our results surprisingly indicate that the magnitude of π-π interactions normalized both per number of total atoms and carbon atoms increases signifi- cantly with the relative number of hydrogen atoms in the studied systems.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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