Study of polycyclic aromatic hydrocarbons adsorbed on graphene using density functional theory with empirical dispersion correction

Abstract

The interaction of polycyclic aromatic hydrocarbon molecules with hydrogen-terminated graphene is studied using density functional theory with empirical dispersion correction. The effective potential energy surfaces for the interaction of benzene, C(6)H(6), naphthalene, C(10)H(8), coronene, C(24)H(12), and ovalene, C(32)H(14), with hydrogen-terminated graphene are calculated as functions of the molecular displacement along the substrate. The potential energy surfaces are also described analytically using the lowest harmonics of the Fourier expansion. It is shown that inclusion of the dispersive interaction, which is the most important contribution to the binding of these weakly bound systems, does not change the shape of the interaction energy surfaces or the value of the barriers to the motion of polycyclic aromatic hydrocarbon molecules on graphene. The potential energy surfaces are used in the estimation of the friction forces acting on the molecules along the direction of motion. These results underpin the modelling, using density functional theory, of electromechanical devices based on the relative vibrations of graphene layers and telescoping carbon nanotubes.

Interlayer interaction and related properties of bilayer hexagonal boron nitride: ab initio study

“…55 Shifting the layers by one and half of the bond length more in the armchair direction results in the AA stacking in which all atoms of the top layer are located on top of the equivalent atoms of the bottom layer and the interlayer interaction energy reaches its maximum for the given interlayer distance. The energy of the AA stacking relative to the AB one is about 18 meV/atom (Tables 1 and 2), close to the DFT data for graphene 7,[59][60][61][64][65][66] and for bilayer 55 and bulk 49,51,55 h-BN as well as LMP2 values of about 20 meV/atom 55 for bilayer and bulk h-BN. The potential energy surface for h-BN layers aligned in the opposite directions ( Fig.…”

“…We should note that the possibility to accurately approximate potential energy surfaces by expressions containing only the first Fourier harmonics has been previously demonstrated for interaction between graphene layers 60,61,66,88 and between carbon nanotube walls, both for infinite commensurate walls 81,[89][90][91][92] and in the case where corrugations of the potential surface are determined by the contribution of edges 93 or defects. 81 Thus we can expect that analogous expressions can describe potential energy surfaces for other layered materials with the van der Waals interaction between layers or for translational motion of large molecules physically adsorbed on crystal surfaces.…”

“…55,59,60,86 On the other hand, inclusion of vdW interactions almost does not affect the potential energy surface at a given interlayer distance. 54,55,59,60,66 Thus it is reasonable to study the potential energy surface at the equilibrium interlayer distance known from the experiments rather than rely on the values provided by the DFT methods.…”

“…65 , LDA calculations for bilayer graphene), 1 − 1.5 meV/atom (Ref. 66 , DFT-D calculations for polycyclic aromatic hydrocarbons adsorbed on graphene), 2.6 meV/atom (Ref. 59 ), 2.07 meV/atom (Ref.…”

Why twisting angles are diverse in graphene Moiré patterns?

“…36,37 There are mainly two solutions for this issue. The first method is to develop a vdW-corrected DFT (DFT-D) approach, where the long-range interaction is described directly by the vdW potential [38][39][40][41][42] or is included through a density-density interaction in the DFT scheme 43 . The second method is to include the π-overlap through some empirical potential terms with empirical parameters fitted to experiment or DFT-D results.…”