Fast and accurate computational modeling of adsorption on graphene: a dispersion interaction challenge

Abstract

Understanding molecular interactions of graphene is a question of key importance to design new materials and catalytic systems for practical usage. Although for small models good accuracy was demonstrated in theoretical analysis with ab initio and density functional methods, the application to real-size systems with thousands of atoms is currently hardly possible on routine bases due to the high computational cost. In the present study we report that incorporation of dispersion correction led to the principal improvement in the description of graphene systems at a semi-empirical level. The accuracy and the scope of the calculations were explored for a wide range of molecules adsorbed on graphene surfaces (H2, N2, CO, CO2, NH3, CH4, H2O, benzene, naphthalene, coronene, ovalene and cyclohexane). As a challenging parameter, the calculated adsorption energy of aromatic hydrocarbons on graphene Eads = -1.8 ± 0.1 kcal mol(-1) (per one carbon atom) at the PM6-DH2 level was in excellent agreement with the experimentally determined value of Eads = -1.7 ± 0.3 kcal mol(-1). The dispersion corrected semi-empirical method was found to be a remarkable computational tool suitable for everyday laboratory studies of real-size graphene systems. Significant performance improvement (ca. 10(3) times faster) and excellent accuracy were found as compared to the ωB97X-D density functional calculations.

Molecular Dynamics of Cellulose Amphiphilicity at the Graphene–Water Interface

“…graphene core at the PM6-DH2 level; 40 beyond the simplicity of the above assumption, the slightly higher estimate we find could reflect an enhanced effect due to multiple CH-π interactions, as has been suggested elsewhere. 44 On solvation, modelled by COSMO implicit solvent, the total PM6-DH2 interaction energy drops to an average of -549 kcal mol -1 over the last 100 ns (Figure 5b), leading to an estimate of -2.9 kcal mol -1 per CH-π interaction.…”

Adsorption and STM imaging of polycyclic aromatic hydrocarbons on graphene

“…This can be explained by the lack of quadrupole-quadrupole interactions in our model (which remains at the dipole-dipole interaction level), which is important for small molecules, and decreases with the size of the molecule for symmetry reasons, like in the graphene-graphene configuration, for example. In the coronene case, the energy range is around 71-85 meV/atom, in good agreement with quantum chemical calculations at the PM6-DH2 level [61], and DFT calculations using the optB88-vdW functional [60]. As another comparison, the energy value found in this case using the vdW-DF functional gives a slightly lower result, around 63 meV/atom [60].…”

Water Clusters on Graphitic Carbon Surfaces

“…It is expected that the formation of water clusters on the surface will probably result in excessively large interaction energy for an isolated water molecule. Molecular-level understanding of the interactions of water clusters with graphitic materials and their influence on macroscopic phenomena is certainly among the main topics of scientists [4][5][6][7][8][9][10][11][12][13][14][21][22][23][24][25][26]. However, at the quantum mechanical level, such understanding is still far from complete, with the most fundamental matter between water molecules and any carbon surface yet to be fully established.…”

“…When water is adsorbed on the substrates, it will minimize its energy by adopting a specific structure to that surface, and that the geometry is dependent on the relative strength of the water-surface interaction and the water-water interaction. In the past two decades, the interactions of water molecules with various graphitic materials, including graphene, carbon nanotubes, and graphite, have attracted wide spread attention among experimental and computational chemists [4][5][6][7][8][9][10][11][12][13][14][15][16]. The understanding of the water interactions with graphenes or single walled carbon nanotubes (SWCNTs) is very important for potential applications of these materials.…”